Comparison of black–white disparities in preterm birth between Canada and the United States

Background:

A higher risk of preterm birth among black women than among white women is well established in the United States. We compared differences in preterm birth between non-Hispanic black and white women in Canada and the US, hypothesizing that disparities would be less extreme in Canada given the different historical experiences of black populations and Canada’s universal health care system.

Methods:

Using data on singleton live births in Canada and the US for 2004–2006, we estimated crude and adjusted risk ratios and risk differences in preterm birth (< 37 wk) and very preterm birth (< 32 wk) among non-Hispanic black versus non-Hispanic white women in each country. Adjusted models for the US were standardized to the covariate distribution of the Canadian cohort.

Results:

In Canada, 8.9% and 5.9% of infants born to black and white mothers, respectively, were preterm; the corresponding figures in the US were 12.7% and 8.0%. Crude risk ratios for preterm birth among black women relative to white women were 1.49 (95% confidence interval [CI] 1.32 to 1.66) in Canada and 1.57 (95% CI 1.56 to 1.58) in the US (p value for heterogeneity [p_H] = 0.3). The crude risk differences for preterm birth were 2.94 (95% CI 1.91 to 3.96) in Canada and 4.63 (95% CI 4.56 to 4.70) in the US (p_H = 0.003). Adjusted risk ratios for preterm birth (p_H = 0.1) were slightly higher in Canada than in the US, whereas adjusted risk differences were similar in both countries. Similar patterns were observed for racial disparities in very preterm birth.

Interpretation:

Relative disparities in preterm birth and very preterm birth between non-Hispanic black and white women were similar in magnitude in Canada and the US. Absolute disparities were smaller in Canada, which reflects a lower overall risk of preterm birth in Canada than in the US in both black and white populations.In the United States, a higher risk of preterm birth among black women than among white women is well established.^1–3 This racial disparity is of great concern because preterm birth is a leading cause of perinatal mortality and is predictive of developmental problems and adverse health outcomes later in life.⁴ The underlying causes of the racial disparity in preterm birth in the US are not well understood, although research has suggested contributing roles for a wide range of factors, including socioeconomic disadvantage,⁵ poor neighbourhood conditions (e.g., poverty, crime),^5,6 lack of access to health care,⁷ psychosocial stress,⁸ racial discrimination⁹ and adverse health behaviours.¹⁰Rates of preterm birth have consistently been lower in Canada than in the US.^11,12 However, in contrast to the US, little is known about differences in rates by race or ethnicity in Canada. There is evidence that African-born and Caribbean-born women in the provinces of Quebec and Ontario have higher rates of preterm birth than Canadian-born women.^13–15 Although the magnitude of these differences is smaller than the disparity in preterm births between black and white women in the US,¹⁶ foreign-born black women in the US have been found to be at lower risk of preterm birth than US-born black women.^17,18In both Canada and the US, socioeconomic conditions at both individual and neighbourhood levels are important predictors of preterm birth.^19–21 Although the income gap between black and white people is markedly smaller in Canada than in the US,²² black populations in both countries have lower education levels, higher unemployment rates and a greater likelihood of living in low-quality neighbourhoods compared with white populations.²³ Canada and the US share similar social and economic influences, yet the historical experiences of black populations and the social welfare systems (e.g., universal health care) are quite different in the 2 countries. Black people constitute about 13% of the total US population, but only about 3% of the Canadian population.^24,25 The overwhelming majority of Canada’s black population are immigrants who entered the country after 1960 and their descendants, whereas more than 85% of black Americans can trace their ancestry 3 or more generations in the US, with most being descendants of slaves.²²The objectives of our study are twofold. First, using data from a new cohort linking birth registrations with information from the 2006 Canadian long-form census, we present Canada-wide estimates of differences in preterm birth rates between black and white populations. Second, we use comparable methodology to compare racial differences in preterm birth rates between Canada and the US. Given different historical experiences of black populations in the 2 countries, as well as Canada’s commitment to universal health care and its general perception as a more egalitarian society than the US,²² we hypothesized that we would observe smaller racial disparities in the rates in Canada than in the US.     

Long-distance travel for birthing among Indigenous and non-Indigenous pregnant people in Canada

BACKGROUND:For Indigenous Peoples in Canada, birthing on or near traditional territories in the presence of family and community is of foundational cultural and social importance. We aimed to evaluate the association between Indigenous identity and distance travelled for birth in Canada.METHODS:We obtained data from the Maternity Experiences Survey, a national population-based sample of new Canadian people aged 15 years or older who gave birth (defined as mothers) and were interviewed in 2006–2007. We compared Indigenous with non-Indigenous Canadian-born mothers and adjusted for geographic and sociodemographic factors and medical complications of pregnancy using multivariable logistic regression. We categorized the primary outcome, distance travelled for birth, as 0 to 49, 50 to 199 or 200 km or more.RESULTS:We included 3100 mothers living in rural or small urban areas, weighted to represent 31 100 (1800 Indigenous and 29 300 non-Indigenous Canadian-born mothers). We found that travelling 200 km or more for birth was more common among Indigenous compared with non-Indigenous mothers (9.8% v. 2.0%, odds ratio [OR] 5.45, 95% confidence interval [CI] 3.52–8.48). In adjusted analyses, the association between Indigenous identity and travelling more than 200 km for birth was even stronger (adjusted OR 16.44, 95% CI 8.07–33.50) in rural regions; however, this was not observed in small urban regions (adjusted OR 1.04, 95% CI 0.37–2.91).INTERPRETATION:Indigenous people in Canada experience striking inequities in access to birth close to home compared with non-Indigenous people, primarily in rural areas and independently of medical complications of pregnancy. This suggests inequities are rooted in the geographic distribution of and proximal access to birthing facilities and providers for Indigenous people.

Access to birth close to home, surrounded by loved ones, is taken for granted by most Canadians. The societal importance of family support during birthing has been highlighted during the severe acute respiratory syndrome and COVID-19 pandemics, despite the known and potentially fatal risks to hospital visitors, because people in labour have been one of the few patient groups exempt from visitor restrictions.^1,2 For residents living in rural areas of Canada, long-distance travel for birth is a reality that is becoming increasingly common in some regions because of closures of obstetrical services in smaller community hospitals.³ This is only partially mitigated by the revitalization of rural midwifery practice.^4,5Emerging evidence shows that the frequency of adverse medical events during labour and delivery for rural populations is similar for births that take place close to home and births for which people travel because of an absence of services close to home.^3,4,6 Less is known about the impacts of travel for birth on breastfeeding rates, maternal mental health and family functioning. Several studies have documented the negative impacts of birthing away from home with respect to maternal satisfaction and birth experience.^7–10 This evidence is particularly compelling for Indigenous populations for whom birthing on or near traditional territories in the presence of family and community is a long-standing practice of foundational cultural and social importance that contributes to well-being, cultural continuity and kinship.^7–12The striking isolation, family disruption and racism experienced by Indigenous people who are forced to travel alone for birth as a result of externally imposed federal “evacuation for birth” policies¹¹ has been met with a series of policy initiatives to support return of birth to rural and remote Indigenous communities. ^13–15 In April 2017, then federal Minister of Health Dr. Jane Philpott, committed to “a path to be able to return the cries of birth” to Indigenous communities and funding to support travel for a companion when Indigenous people living in rural and remote areas needed to travel away from home for birth.¹⁶ Before 2017, Indigenous pregnant people often travelled and birthed away from home alone without family or community support, because escorts were not deemed medically necessary. Although these initiatives have improved access to Indigenous perinatal programming and Indigenous birth attendant support in some local areas, over the past decade there has not been any substantial expansion of Indigenous birthing facilities outside of urban centres in Canada and at least 1 remote Indigenous birthing facility has closed.¹⁷Given this dynamic policy context, the national scope and Indigenous identifiers in the Canadian Maternity Experiences Survey (MES) provides a unique opportunity to quantify how often Indigenous and non-Indigenous people are travelling away from home for birth and to evaluate the association between Indigenous and non-Indigenous identity and distance travelled for birth in Canada.     

Preterm birth and stillbirth rates during the COVID-19 pandemic: a population-based cohort study

BACKGROUND:Conflicting reports have emerged for rates of preterm births and stillbirths during the COVID-19 pandemic. Most of these reports did not account for natural variation in these rates. We aimed to evaluate variations in preterm birth and stillbirth rates before and during the COVID-19 pandemic in Ontario, Canada.METHODS:We conducted a retrospective cohort study using linked population health administrative databases of pregnant people giving birth in any hospital in Ontario between July 2002 and December 2020. We calculated preterm birth and stillbirth rates. We assessed preterm birth at 22–28, 29–32 and 33–36 weeks’ gestation, and stillbirths at term and preterm gestation. We used Laney control P′ charts for the 18-year study period (6-mo observation periods) and interrupted time-series analyses for monthly rates for the most recent 4 years.RESULTS:We evaluated 2 465 387 pregnancies, including 13 781 that resulted in stillbirth. The mean preterm birth rate for our cohort was 7.96% (range 7.32%–8.59%). From January to December 2020, we determined that the preterm birth rate in Ontario was 7.87%, with no special cause variation. The mean stillbirth rate for the cohort was 0.56% (range 0.48%–0.70%). From January to December 2020, the stillbirth rate was 0.53%, with no special cause variation. We did not find any special cause variation for preterm birth or stillbirth subgroups. We found no changes in slope or gap between prepandemic and pandemic periods using interrupted time-series analyses.INTERPRETATION:In Ontario, Canada, we found no special cause variation (unusual change) in preterm birth or stillbirth rates, overall or by subgroups, during the first 12 months of the COVID-19 pandemic compared with the previous 17.5 years.

Preterm birth (birth before 37 weeks’ gestation) is a leading cause of mortality and morbidities in the neonatal period,¹ childhood and adulthood.² Stillbirth has devastating consequences for families.³ The causes of both preterm birth and stillbirth are multifactorial. During the pandemic, reports described reductions in preterm birth rates in Denmark,⁴ the Netherlands,⁵ Ireland⁶ and the United States.⁷ At the same time, increases in stillbirth rates were reported from the United Kingdom,⁸ Italy,⁹ Nepal¹⁰ and India,¹¹ with or without changes in rates of preterm births. Meta-analyses have emerged with differing conclusions.^12,13 Some speculated reasons for reductions in preterm births included reductions in physical activity during pregnancy, reduced stress related to work–life balance, less exposure to infection, fewer medical interventions, reduced travel and pollution,¹⁴ and improved hygiene and rest. Proposed reasons for increases in preterm birth rates include higher stress due to worry about the pandemic, employment or financial challenges, home schooling and reduced maternity services.¹⁵ Less stringent fetal surveillance from reduced attendance at medical appointments for fear of infection, cancellation of face-to-face appointments and reduced staffing for maternity services are possible reasons for increased rates of stillbirths. Thus, it is important to evaluate preterm births and stillbirths simultaneously to understand the true impact.¹⁶Some previous reports compared preterm birth and stillbirth rates during the pandemic to similar time periods in the past few years. However, within a jurisdiction, these rates are known to fluctuate between epochs¹⁷ and, thus, it is preferable to evaluate rates over longer periods to establish whether observed variations are usual (common cause variation) or unusual (special cause variation). Our objective was to evaluate whether the COVID-19 pandemic affected preterm birth or stillbirth rates in Ontario by comparing rates for the early COVID-19 pandemic time period with rates from the previous 17.5 years to identify patterns of variation.     

Effects of prenatal multimicronutrient supplementation on pregnancy outcomes: a meta-analysis

Background

Reduced intake of micronutrients during pregnancy exposes women to nutritional deficiencies and may affect fetal growth. We conducted a systematic review to examine the efficacy of prenatal supplementation with multimicronutrients on pregnancy outcomes.

Methods

We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library for relevant articles published in English up to December 2008. We also searched the bibliographies of selected articles as well as clinical trial registries. The primary outcome was low birth weight; secondary outcomes were preterm birth, small-for-gestational-age infants, birth weight and gestational age.

Results

We observed a significant reduction in the risk of low birth weight among infants born to women who received multimicronutrients during pregnancy compared with placebo (relative risk [RR] 0.81, 95% confidence interval [CI] 0.73–0.91) or iron–folic acid supplementation (RR 0.83, 95% CI 0.74–0.93). Birth weight was significantly higher among infants whose mothers were in the multimicronutrient group than among those whose mothers received iron–folic acid supplementation (weighted mean difference 54 g, 95% CI 36 g–72 g). There was no significant differences in the risk of preterm birth or small-for-gestational-age infants between the 3 study groups.

Interpretation

Prenatal multimicronutrient supplementation was associated with a significantly reduced risk of low birth weight and with improved birth weight when compared with iron–folic acid supplementation. There was no significant effect of multimicronutrient supplementation on the risk of preterm birth or small-for-gestational-age infants.Nutrition plays an important role in the growth and development of the fetus. Studies of the nutritional status of pregnant women during the Dutch famine revealed increased risks of infertility, abortion, fetal intrauterine growth restriction and perinatal mortality among malnourished women.¹ In many parts of the world, a similar situation exists for many pregnant women with respect to nutrition. Overall, the diet of pregnant women has been reported to be deficient in calories and micronutrients.² Both macro- and micronutrients are important for a woman to sustain pregnancy and for appropriate growth of the fetus.The exact mechanisms of how supplementation with micronutrients can affect pregnancy outcomes are not completely understood. Possible mechanisms for beneficial effects include a generalized improvement in the immune function of women, with a reduced incidence of infections and subsequent reduced incidence of preterm birth;³ improved energy metabolism and anabolic processes in the mother, with a reduced incidence of fetal intrauterine growth restriction;³ improved ability to respond to stress;³ expansion of plasma volume secondary to fluid retention, with subsequent improvements in fetal growth;⁴ improved hemoglobin levels;⁵ and increased absorption of iron related to intake of vitamin C and riboflavin, with subsequent improvement in hemoglobin levels.⁵Potential disadvantages include adverse interactions of micronutrients when supplied in combination;⁶ enhanced or reduced absorption of one nutrient by other nutrients (e.g., interaction between iron and vitamin C, and iron and zinc);⁷ deleterious effects on the fetus and the mother from overdose of any one component (e.g., vitamin A overdose);⁶ and cost.⁶Potential barriers include the lack of well-defined government policies on maternal health and nutrition.⁶ A multicomponent approach has been criticized from the standpoint that some micronutrients may be necessary, some may not be needed and some may even be harmful.² Generalized or mass supplementation with multimicronutrients may have different effects on pregnancy outcomes depending on the underlying nutritional status of the women.On the basis of a systematic review performed in 2005, the World Health Organization currently recommends iron–folic acid supplementation for all pregnant women.^8,9 The review reported that multimicronutrient supplementation during pregnancy were more efficacious than 2 or fewer micronutrients in reducing the rates of low birth weight and small-for-gestational-age births. However, when multimicronutrients were compared with iron–folic acid supplementation, no evidence of a difference was noted.⁷ Further research in this area was encouraged because information was derived from a few reports. Since then, several randomized controlled trials have evaluated the efficacy of multimicronutrients and have reported varied results. With advancement in our knowledge from recently reported trials,¹⁰ we conducted a systematic review and meta-analysis of the efficacy of supplementation with multimicronutrients during pregnancy in reducing the rates of low birth weight, preterm birth and small-for-gestational-age births compared with placebo or iron–folic acid supplementation.     

Resting heart rate and all-cause and cardiovascular mortality in the general population: a meta-analysis

Background:

Data on resting heart rate and risk of all-cause and cardiovascular mortality are inconsistent; the magnitude of associations between resting heart rate and risk of all-cause and cardiovascular mortality varies across studies. We performed a meta-analysis of prospective cohort studies to quantitatively evaluate the associations in the general population.

Methods:

We searched PubMed, Embase and MEDLINE from inception to Jan. 1, 2015. We used a random-effects model to combine study-specific relative risks and 95% confidence intervals (CIs). We used restricted cubic spline functions to assess the dose–response relation.

Results:

A total of 46 studies were included in the meta-analysis, involving 1 246 203 patients and 78 349 deaths for all-cause mortality, and 848 320 patients and 25 800 deaths for cardiovascular mortality. The relative risk with 10 beats/min increment of resting heart rate was 1.09 (95% CI 1.07–1.12) for all-cause mortality and 1.08 (95% CI 1.06–1.10) for cardiovascular mortality. Compared with the lowest category, patients with a resting heart rate of 60–80 beats/min had a relative risk of 1.12 (95% CI 1.07–1.17) for all-cause mortality and 1.08 (95% CI 0.99–1.17) for cardiovascular mortality, and those with a resting heart rate of greater than 80 beats/min had a relative risk of 1.45 (95% CI 1.34–1.57) for all-cause mortality and 1.33 (95% CI 1.19–1.47) for cardiovascular mortality. Overall, the results did not differ after adjustment for traditional risk factors for cardiovascular disease. Compared with 45 beats/min, the risk of all-cause mortality increased significantly with increasing resting heart rate in a linear relation, but a significantly increased risk of cardiovascular mortality was observed at 90 beats/min. Substantial heterogeneity and publication bias were detected.

Interpretation:

Higher resting heart rate was independently associated with increased risks of all-cause and cardiovascular mortality. This indicates that resting heart rate is a predictor of all-cause and cardiovascular mortality in the general population.Resting heart rate is a familiar, straightforward and inexpensive-to-measure clinical variable, and it can be modified by a number of factors, such as physical activity, psychologic stress, smoking, intake of omega-3 fatty acids and medications.^1–4 Higher heart rate has been linked to increased risks of cardiovascular disease and premature mortality through a multitude of actions, including its detrimental effects on progression of coronary atherosclerosis, on occurrence of myocardial ischemia and ventricular arrhythmia, on left ventricular function and on circulating levels of inflammatory markers.^5–7 However, measurement of resting heart rate has not been recommended in American and European guidelines on risk assessment of cardiovascular disease.^8,9 The major reasons for this may be that the magnitude of risk with each increment of higher resting heart rate has been inconsistent among studies, and that resting heart rate may not be an independent predictor because higher heart rate coexists with traditional risk factors of cardiovascular disease.^10–13 In addition, data are lacking on the dose–response relation between resting heart rate and all-cause and cardiovascular mortality,^5,9 although a previous review showed a continuous increase in risk with resting heart rate above 60 beats/min.⁵Therefore, we conducted a meta-analysis of prospective cohort studies involving the general population, following the MOOSE checklist,¹⁴ to assess the risk of all-cause and cardiovascular mortality associated with each increment of 10 beats/min; to evaluate the possible dose–response relation by restricted cubic spline functions and by pooling risks of all-cause and cardiovascular mortality for comparable categories of resting heart rate (60–80 beats/min and > 80 beats/min); and to evaluate the effect of traditional risk factors of cardiovascular disease on the association of resting heart rate with risk of all-cause and cardiovascular mortality.     

Diversity among health care leaders in Canada: a cross-sectional study of perceived gender and race

Background:Diverse health care leadership teams may improve health care experiences and outcomes for patients. We sought to explore the race and gender of hospital and health ministry executives in Canada and compare their diversity with that of the populations they serve.Methods:This cross-sectional study included leaders of Canada’s largest hospitals and all provincial and territorial health ministries. We included individuals listed on institutional websites as part of the leadership team if a name and photo were available. Six reviewers coded and analyzed the perceived race and gender of leaders, in duplicate. We compared the proportion of racialized health care leaders with the race demographics of the general population from the 2016 Canadian Census.Results:We included 3056 leaders from 135 institutions, with reviewer concordance on gender for 3022 leaders and on race for 2946 leaders. Reviewers perceived 37 (47.4%) of 78 health ministry leaders as women, and fewer than 5 (< 7%) of 80 as racialized. In Alberta, Saskatchewan, Prince Edward Island and Nova Scotia, provinces with a centralized hospital executive team, reviewers coded 36 (50.0%) of 72 leaders as women and 5 (7.1%) of 70 as racialized. In British Columbia, New Brunswick and Newfoundland and Labrador, provinces with hospital leadership by region, reviewers perceived 120 (56.1%) of 214 leaders as women and 24 (11.5%) of 209 as racialized. In Manitoba, Ontario and Quebec, where leadership teams exist at each hospital, reviewers perceived 1326 (49.9%) of 2658 leaders as women and 243 (9.2%) of 2633 as racialized. We calculated the representation gap between racialized executives and the racialized population as 14.5% for British Columbia, 27.5% for Manitoba, 20.7% for Ontario, 12.4% for Quebec, 7.6% for New Brunswick, 7.3% for Prince Edward Island and 11.6% for Newfoundland and Labrador.Interpretation:In a study of more than 3000 health care leaders in Canada, gender parity was present, but racialized executives were substantially under-represented. This work should prompt health care institutions to increase racial diversity in leadership.

Race and gender-based disparities in health care leadership^1–4 may negatively affect the health of marginalized patients.^5,6 Diverse leadership is an integral step in establishing equitable health care institutions that serve the needs of all community members.⁷ Many barriers prevent racialized people, women and gender nonbinary individuals from attaining leadership positions, including reduced access to networking opportunities, ^8–10 discrimination from patients and colleagues^2,11–13 and an institutional culture that views white, male leaders as most effective. ^14,15 The intersectional effects of discrimination may intensify these barriers for racialized women and nonbinary people.^16,17 Fundamentally, diversity and inclusion in our institutions is important on the basis of basic human rights for all people.¹⁸Health care leadership in Europe and the United States is thought to lack gender and racial diversity.^19–22 The degree to which these imbalances exist across Canadian health care institutions is not clear. Despite past evidence that men hold a disproportionate number of health care leadership positions in Canada,^23,24 a recent study noted gender parity among leaders of provincial and territorial ministries of health.²⁵ Among university faculty^26,27 and administration, ²⁸ racialized individuals appear to be under-represented, suggesting that a similar trend may exist in health care leadership.Race and gender can be studied in many ways.²⁹ Perceived race is a measure of “the race that others believe you to be,” and these assessments “influence how people are treated and form the basis of racial discrimination including nondeliberate actions that nonetheless lead to socioeconomic inequities.”²⁹ Similarly, perceived gender refers to an observer’s assumptions about a person’s gender, which can lead to differential and unfair treatment. ³⁰ Assessing perceived race and gender provides crucial insights into the ways in which social inequalities are informed and produced.²⁹ In this study, we sought to identify the perceived race and gender of hospital executive leaders in Canada and of nonelected leaders of the provincial and territorial health ministries. Furthermore, we wanted to analyze how the perceived racial composition of health care leadership compares with the racial composition of the population in the geographic areas that these leaders serve.     

Outcomes in patients with and without disability admitted to hospital with COVID-19: a retrospective cohort study

Background:Disability-related considerations have largely been absent from the COVID-19 response, despite evidence that people with disabilities are at elevated risk for acquiring COVID-19. We evaluated clinical outcomes in patients who were admitted to hospital with COVID-19 with a disability compared with patients without a disability.Methods:We conducted a retrospective cohort study that included adults with COVID-19 who were admitted to hospital and discharged between Jan. 1, 2020, and Nov. 30, 2020, at 7 hospitals in Ontario, Canada. We compared in-hospital death, admission to the intensive care unit (ICU), hospital length of stay and unplanned 30-day readmission among patients with and without a physical disability, hearing or vision impairment, traumatic brain injury, or intellectual or developmental disability, overall and stratified by age (≤ 64 and ≥ 65 yr) using multivariable regression, controlling for sex, residence in a long-term care facility and comorbidity.Results:Among 1279 admissions to hospital for COVID-19, 22.3% had a disability. We found that patients with a disability were more likely to die than those without a disability (28.1% v. 17.6%), had longer hospital stays (median 13.9 v. 7.8 d) and more readmissions (17.6% v. 7.9%), but had lower ICU admission rates (22.5% v. 28.3%). After adjustment, there were no statistically significant differences between those with and without disabilities for in-hospital death or admission to ICU. After adjustment, patients with a disability had longer hospital stays (rate ratio 1.36, 95% confidence interval [CI] 1.19–1.56) and greater risk of readmission (relative risk 1.77, 95% CI 1.14–2.75). In age-stratified analyses, we observed longer hospital stays among patients with a disability than in those without, in both younger and older subgroups; readmission risk was driven by younger patients with a disability.Interpretation:Patients with a disability who were admitted to hospital with COVID-19 had longer stays and elevated readmission risk than those without disabilities. Disability-related needs should be addressed to support these patients in hospital and after discharge.

A successful public health response to the COVID-19 pandemic requires accurate and timely identification of, and support for, high-risk groups. There is increasing recognition that marginalized groups, including congregate care residents, racial and ethnic minorities, and people experiencing poverty, have elevated incidence of COVID-19.^1,2 Older age and comorbidities such as diabetes are also risk factors for severe COVID-19 outcomes.^3,4 One potential high-risk group that has received relatively little attention is people with disabilities.The World Health Organization estimates there are 1 billion people with disabilities globally.⁵ In North America, the prevalence of disability is 20%, with one-third of people older than 65 years having a disability.⁶ Disabilities include physical disabilities, hearing and vision impairments, traumatic brain injury and intellectual or developmental disabilities.^5,6 Although activity limitations experienced by people with disabilities are heterogeneous,^5,6 people with disabilities share high rates of risk factors for acquiring COVID-19, including poverty, residence in congregate care and being members of racialized communities.^7–9 People with disabilities may be more reliant on close contact with others to meet their daily needs, and some people with disabilities, especially intellectual developmental disabilities, may have difficulty following public health rules. Once they acquire SARS-CoV-2 infection, people with disabilities may be at risk for severe outcomes because they have elevated rates of comorbidities.¹⁰ Some disabilities (e.g., spinal cord injuries and neurologic disabilities) result in physiologic changes that increase vulnerability to respiratory diseases and may mask symptoms of acute respiratory disease, which may delay diagnosis.^11–13 There have also been reports of barriers to high-quality hospital care for patients with disabilities who have COVID-19, including communication issues caused by the use of masks and restricted access to support persons.^14–17Some studies have suggested that patients with disabilities and COVID-19 are at elevated risk for severe disease and death, with most evaluating intellectual or developmental disability.^13,18–26 Yet, consideration of disability-related needs has largely been absent from the COVID-19 response, with vaccine eligibility driven primarily by age and medical comorbidity, limited accommodations made for patients with disabilities who are in hospital, and disability data often not being captured in surveillance programs.^14–17 To inform equitable pandemic supports, there is a need for data on patients with a broad range of disabilities who have COVID-19. We sought to evaluate standard clinical outcomes in patients admitted to hospital with COVID-19²⁷ (i.e., in-hospital death, intensive care unit [ICU] admission, hospital length of stay and unplanned 30-d readmission) for patients with and without a disability, overall and stratified by age. We hypothesized that patients with a disability would have worse outcomes because of a greater prevalence of comorbidities,¹⁰ physiologic characteristics that increase morbidity risk^11–13 and barriers to high-quality hospital care.^14–17     

Rates and determinants of seasonal influenza vaccination in pregnancy and association with neonatal outcomes

Background:

There is growing evidence that seasonal influenza vaccination in pregnancy has benefits for mother and baby. We determined influenza vaccination rates among pregnant women during the 2 nonpandemic influenza seasons following the 2009 H1N1 pandemic, explored maternal factors as predictors of influenza vaccination status and evaluated the association between maternal influenza vaccination and neonatal outcomes.

Methods:

We used a population-based perinatal database in the province of Nova Scotia, Canada, to examine maternal vaccination rates, determinants of vaccination status and neonatal outcomes. Our cohort included women who gave birth between Nov. 1, 2010, and Mar. 31, 2012. We compared neonatal outcomes between vaccinated and unvaccinated women using logistic regression analysis.

Results:

Overall, 1958 (16.0%) of 12 223 women in our cohort received the influenza vaccine during their pregnancy. Marital status, parity, location of residence (rural v. urban), smoking during pregnancy and maternal influenza risk status were determinants of maternal vaccine receipt. The odds of preterm birth was lower among infants of vaccinated women than among those of nonvaccinated women (adjusted odds ratio [OR] 0.75, 95% confidence interval [CI] 0.60–0.94). The rate of low-birth-weight infants was also lower among vaccinated women (adjusted OR 0.73, 95% CI 0.56–0.95).

Interpretation:

Despite current guidelines advising all pregnant women to receive the seasonal influenza vaccine, influenza vaccination rates among pregnant women in our cohort were low in the aftermath of the 2009 H1N1 pandemic. This study and others have shown an association between maternal influenza vaccination and improved neonatal outcomes, which supports stronger initiatives to promote vaccination during pregnancy.Influenza viruses are the leading cause of serious wintertime respiratory morbidity worldwide. Several studies investigating the effects of influenza-related illness during pregnancy have shown a strong impact on the health of pregnant women in terms of increased rates of hospital admission because of respiratory illness.^1–3 Schanzer and colleagues² found that pregnant women in Canada were at increased risk of influenza-related hospital admission when compared with nonpregnant women of similar age and health status. In addition, influenza-related illness during pregnancy may have a negative impact on neonatal outcomes. A study in Nova Scotia, Canada, showed that infants whose mothers were admitted to hospital because of respiratory illness during influenza season while pregnant were more likely to be small for gestational age and to have lower mean birth weight.⁴By 2007, the cumulative evidence from these and other studies was compelling enough for advisory boards in Canada to recommend routine influenza vaccination for all pregnant women, including those without medical comorbidities.⁵ Despite these recommendations, seasonal vaccination rates among pregnant women have remained low. In a cohort of pregnant women who delivered at the IWK Health Centre, Halifax, from 2006 to 2009, only 20% had received the vaccine during their pregnancy.⁶ Increased vaccination rates among pregnant women were reported for the 2009 H1N1 pandemic year,⁷ but it is unknown whether this has translated into higher rates of seasonal influenza vaccination since then. Studies have shown that concern about vaccine safety is the most commonly cited reason for refusing the vaccine,^8,9 despite much evidence showing it to be safe in pregnancy.¹⁰ A recommendation from a maternity care provider has been shown to be a key factor in increasing vaccination rates.^11,12In light of the growing evidence that influenza vaccination during pregnancy has benefits for both the mother and the infant,^13–18 we evaluated rates of seasonal influenza vaccination among pregnant women in the 2 nonpandemic influenza seasons (2010/11 and 2011/12) following the 2009 H1N1 pandemic. We also assessed whether neonatal outcomes differed between women who received the vaccine during pregnancy and those who did not.     

Association of macrosomia with perinatal and postneonatal mortality among First Nations people in Quebec

Background

High prevalence of infant macrosomia (up to 36%, the highest in the world) has been reported in some First Nations communities in the Canadian province of Quebec and the eastern area of the province of Ontario. We aimed to assess whether infant macrosomia was associated with elevated risks of perinatal and postneonatal mortality among First Nations people in Quebec.

Methods

We calculated risk ratios (RRs) of perinatal and postneonatal mortality by birthweight for gestational age, comparing births to First Nations women (n = 5193) versus women whose mother tongue is French (n = 653 424, the majority reference group) in Quebec 1991–2000.

Results

The prevalence of infant macrosomia (birthweight for gestational age > 90th percentile) was 27.5% among births to First Nations women, which was 3.3 times (confidence interval [CI] 3.2–3.5) higher than the prevalence (8.3%) among births to women whose mother tongue is French. Risk ratios for perinatal mortality among births to First Nations women were 1.8 (95% CI 1.3–2.5) for births with weight appropriate for gestational age, 4.1 (95% CI 2.4–7.0) for small-for-gestational-age (< 10th percentile) births and < 1 (not significant) for macrosomic births compared to births among women whose mother tongue is French. The RRs for postneonatal mortality were 4.3 (95% CI 2.7–6.7) for infants with appropriate-for-gestational-age birthweight and 8.3 (95% CI 4.0–17.0) for infants with macrosomia.

Interpretation

Macrosomia was associated with a generally protective effect against perinatal death, but substantially greater risks of postneonatal death among births to First Nations women in Quebec versus women whose mother tongue is French.A trend toward higher birthweights has emerged in recent decades.^1–3 Reflected in this trend is a rise in the prevalence of infant macrosomia, commonly defined as either a birthweight greater than 4000 g or a birthweight for gestational age greater than the 90th percentile relative to a fetal growth standard.^4–8 Maternal obesity, impaired glucose tolerance and gestational diabetes mellitus are important risk factors for infant macrosomia^9,10 and are known to afflict a much higher proportion of people in Aboriginal populations than in the general population.^11–14 This is true especially for Aboriginal populations in which a traditional lifestyle has changed to a less physically active, modern lifestyle in recent decades. A high prevalence of infant macrosomia (up to 36%, which, to the best of our knowledge, is the highest in the world) has been reported in some First Nations communities of Quebec and eastern Ontario in Canada.^15–17 However, little is known about the implications of this high prevalence for perinatal and infant health of First Nations people in these regions. We examined whether infant macrosomia was associated with increased risk for perinatal and postneonatal death among First Nations infants in Quebec.     

Association between parity and risk of suicide among parous women

Background

There are limited empirical data to support the theory of a protective effect of parenthood against suicide, as proposed by Durkheim in 1897. I conducted this study to examine whether there is an association between parity and risk of death from suicide among women.

Methods

The study cohort consisted of 1 292 462 women in Taiwan who had a first live birth between Jan. 1, 1978, and Dec. 31, 1987. The women were followed up from the date of their first birth to Dec. 31, 2007. Their vital status was ascertained by means of linking records with data from a computerized mortality database. Cox proportional hazard regression models were used to estimate hazard ratios of death from suicide associated with parity.

Results

There were 2252 deaths from suicide during 32 464 187 person-years of follow-up. Suicide-related mortality was 6.94 per 100 000 person-years. After adjustment for age at first birth, marital status, years of schooling and place of delivery, the adjusted hazard ratio was 0.61 (95% confidence interval [CI] 0.54–0.68) among women with two live births and 0.40 (95% CI 0.35–0.45) among those with three or more live births, compared with women who had one live birth. I observed a significantly decreasing trend in adjusted hazard ratios of suicide with increasing parity.

Interpretation

This study provides evidence to support Durkheim’s hypothesis that parenthood confers a protective effect against suicide.Childbearing is considered to have long-term effects on women’s health.¹ However, little is known about the relation between parity and mortality among women except for cancers of the reproductive organs.²In his book on suicide published in 1897, Durkheim concluded that the rate of death from suicide was lower among married women than among unmarried women because of the effect of parenthood and not marriage per se.³ Three studies since then have explored Durkheim’s hypothesis. In the first, published almost 100 years later, Hoyer and Lund conducted a prospective study in Norway involving 989 949 married women aged 25 years or older who were followed up for 15 years.⁴ They reported a negative association between suicide-related mortality and number of children. In a nested case–control study in Denmark involving 6500 women who committed suicide between Jan. 1, 1981, and Dec. 31, 1997, and 130 000 matched control subjects, Qin and Mortensen found a significantly decreased risk of suicide with increasing number of children.⁵ In the third study, 12 055 pregnant women in Finland were followed up from delivery in 1966 until 2001; the authors found a decreasing trend in suicide-related mortality with increasing parity.¹One reason for the limited empirical evidence exploring Durkheim’s hypothesis may have to do with sample size and study design.⁴ Only studies involving representative suicides from the general population could make it possible to achieve sufficient power to detect the effect of parity on rare events such as suicide.^1,4,5 Even in the prospective study involving 989 949 women followed for 15 years, only 11 deaths from suicide occurred among women with six or more children.⁴In Taiwan, suicide is the eighth leading cause of death among men and the ninth among women. The age-adjusted rate of death from suicide was 19.7 per 100 000 among men and 9.7 among women in 2007.⁶ Suicide rates in Western countries have been generally lower than those in Asian countries.⁷ A consistent increase in the suicide rate since 1999 has been found in Taiwan.⁶ However, most Western countries have had stable or slightly decreasing rates during the 1990s.^8,9 The male:female ratio of suicide is frequently greater than 3:1 in Western countries,⁷ whereas it is 2:1 in Taiwan.¹⁰ High suicide rates among Chinese women have been well documented.¹¹ One explanation is that Chinese women do not benefit from marriage as much as their male counterparts.¹² The sex difference in suicide rates is largely driven by a high rate of suicide among women in Chinese societies.¹¹ In many Western countries, the trend over the past several years has been in the opposite direction: rates among women have been stable or decreasing, whereas rates among men have been increasing.¹² Furthermore, in an epidemiologic study of suicides in Chinese communities, the prevalence of mental illness among people committing suicide was much lower in those communities than in Western societies.¹³Because the previous studies that related parity and suicide-related mortality were carried out in economically developed countries and because different cultural settings might influence suicide patterns,³ I undertook the present study in Taiwan, using a cohort of women who had a first and singleton live birth between Jan. 1, 1978, and Dec. 31, 1987, to explore further Durkheim’s hypothesis.     

Sex ratios among Canadian liveborn infants of mothers from different countries

Background:

There has been much discussion about whether female feticide occurs in certain immigrant groups in Canada. We examined data on live births in Ontario and compared sex ratios in different groups according to the mother’s country or region of birth and parity.

Methods:

We completed a population-based study of 766 688 singleton live births between 2002 and 2007. We used birth records provided by Ontario Vital Statistics for live births in the province between 23 and 41 weeks’ gestation. We categorized each newborn according to the mother’s country or region of birth, namely Canada (n = 486 599), Europe (n = 58 505), South Korea (n = 3663), China (n = 23 818), Philippines (n = 15 367), rest of East Asia (n = 18 971), Pakistan (n = 18 018), India (n = 31 978), rest of South Asia (n = 20 695) and other countries (n = 89 074). We calculated male:female ratios and 95% confidence intervals (CIs) for all live births by these regions and stratified them by maternal parity at the time of delivery (0, 1, 2 or ≥ 3).

Results:

Among infants of nulliparous women, the male:female ratio was about 1.05 overall. As parity increased, the ratio remained unchanged among infants of Canadian-born women. In contrast, the male:female ratio was significantly higher among infants of primiparous women born in South Korea (1.20, 95% CI 1.09–1.34) and India (1.11, 95% CI 1.07–1.15) than among infants of Canadian-born primiparous women. Among multiparous women, those born in India were significantly more likely than Canadian-born women to have a male infant (parity 2, ratio 1.36, 95% CI 1.27–1.46; parity ≥ 3, ratio 1.25, 95% CI 1.09–1.43).

Interpretation:

Our study of male:female ratios in Ontario showed that multiparous women born in India were significantly more likely than multiparous women born in Canada to have a male infant.Although there are some myths about correctly guessing the sex of a fetus,¹ modern-day prenatal ultrasound enables the identification of whether a fetus is a boy or girl with 99% accuracy.² There has been much discussion about whether female fetuses are at higher risk of pregnancy termination than male fetuses in certain ethnic groups. In India, a study of data from the National Family Health Survey for 265 516 births showed a sharp increase in the male:female ratio among second-order births when the firstborn was a girl, and no significant increase when the firstborn was a boy.³ The authors attributed this trend to the practice of selective abortion of female fetuses. A recent editorial⁴ and news item⁵ in CMAJ suggested that female feticide may also be occurring in Canada.⁶ Rather than using live-birth statistics, the Canadian study cited in CMAJ used data from the 2001 and 2006 Canada Census long-form questionnaires, which were completed by 20% of the population and relied on self-reporting of additional information, including the number of family members in a given household.We used contemporary data on live births in Ontario, Canada’s most populous and ethnically diverse province, and compared sex ratios among infants of Canadian-born women with sex ratios in different immigrant groups. We focused on immigrant groups from countries purported to have the highest rates of preference for a son following the birth of one or more daughters.^3–6 We determined whether the male:female ratio increased with increasing parity in certain immigrant groups, as has been previously suggested.^3,6     

Maternal cardiovascular disease after twin pregnancies complicated by hypertensive disorders of pregnancy: a population-based cohort study

Background:People whose singleton pregnancy is affected by hypertensive disorders of pregnancy (HDP) are at risk of future cardiovascular disease. It is unclear, however, whether this association can be extrapolated to twin pregnancies. We aimed to compare the association between HDP and future cardiovascular disease after twin and singleton pregnancies.Methods:We conducted a population-based retrospective cohort study that included nulliparous people in Ontario, Canada, 1992–2017. We compared the future risk of cardiovascular disease among pregnant people from the following 4 groups: those who delivered a singleton without HDP (referent) and with HDP, and those who delivered twins either with or without HDP.Results:The populations of the 4 groups were as follows: 1 431 651 pregnant people in the singleton birth without HDP group; 98 631 singleton birth with HDP; 21 046 twin birth without HDP; and 4283 twin birth with HDP. The median duration of follow-up was 13 (interquartile range 7–20) years. The incidence rate of cardiovascular disease was lowest among those with a singleton or twin birth without HDP (0.72 and 0.74 per 1000 person-years, respectively). Compared with people with a singleton birth without HDP, the risk of cardiovascular disease was highest among those with a singleton birth and HDP (1.47 per 1000 person-years; adjusted hazard ratio [HR] 1.81 [95% confidence interval (CI) 1.72–1.90]), followed by people with a twin pregnancy and HDP (1.07 per 1000 person-years; adjusted HR 1.36 [95% CI 1.04–1.77]). The risk of the primary outcome after a twin pregnancy with HDP was lower than that after a singleton pregnancy with HDP (adjusted HR 0.74 [95% CI 0.57–0.97]), when compared directly.Interpretation:In a twin pregnancy, HDP are weaker risk factors for postpartum cardiovascular disease than in a singleton pregnancy.

Cardiovascular disease has been shown to be the leading cause of death among women.^1–3 Classic risk factors for cardiovascular disease include obesity, diabetes mellitus, hypertension and family history of cardiovascular disease. ³ More recently, an association has been established between a history of hypertensive disorders of pregnancy (HDP) — gestational hypertension and pre-eclampsia — and future risk of cardiovascular disease.^1,4–11 Consequently, some recommend using a history of HDP for cardiovascular disease risk stratification in women.^3,12The leading hypothesis for the pathogenesis of HDP is that it results from abnormal placentation due to impaired trophoblast invasion,^13–16 resulting in reduced placental perfusion.^17–19 This, in turn, leads to abnormal secretion of the angiogenic factors soluble FMS-like tyrosine kinase 1 (sFlt1) and soluble endoglin (sEng),²⁰ which induce endothelial dysfunction and the clinical manifestations of HDP.^19,21–24 The mechanisms underlying the association between HDP and future cardiovascular disease are under debate.²⁵ One hypothesis is that HDP are merely a marker of underlying subclinical or clinical vascular risk factors that predispose a person to both HDP and future cardiovascular disease.A person who is pregnant with twins is at about 3–4 times higher risk of HDP than a person with a singleton pregnancy,^26–33 with rates of 14% and 5%, respectively.³⁴ The higher risk of HDP in twin pregnancies may be due to higher circulating sFlt1 and sEng owing to greater placental mass in twin pregnancies, ^35–37 and less related to the classic vascular risk factors for HDP in a singleton pregnancy. Therefore, a logical question is whether the established higher risk of future cardiovascular disease after singleton pregnancies with HDP also occurs in twin pregnancies with HDP. Limited data are available to answer this question.³⁸ In the current study, we aimed to test the hypothesis that the association between HDP and future cardiovascular disease is less pronounced in twin versus singleton pregnancies.     

A qualitative investigation of smoke-free policies on hospital property

Background:

Many hospitals have adopted smoke-free policies on their property. We examined the consequences of such polices at two Canadian tertiary acute-care hospitals.

Methods:

We conducted a qualitative study using ethnographic techniques over a six-month period. Participants (n = 186) shared their perspectives on and experiences with tobacco dependence and managing the use of tobacco, as well as their impressions of the smoke-free policy. We interviewed inpatients individually from eight wards (n = 82), key policy-makers (n = 9) and support staff (n = 14) and held 16 focus groups with health care providers and ward staff (n = 81). We also reviewed ward documents relating to tobacco dependence and looked at smoking-related activities on hospital property.

Results:

Noncompliance with the policy and exposure to secondhand smoke were ongoing concerns. Peoples’ impressions of the use of tobacco varied, including divergent opinions as to whether such use was a bad habit or an addiction. Treatment for tobacco dependence and the management of symptoms of withdrawal were offered inconsistently. Participants voiced concerns over patient safety and leaving the ward to smoke.

Interpretation:

Policies mandating smoke-free hospital property have important consequences beyond noncompliance, including concerns over patient safety and disruptions to care. Without adequately available and accessible support for withdrawal from tobacco, patients will continue to face personal risk when they leave hospital property to smoke.Canadian cities and provinces have passed smoking bans with the goal of reducing people’s exposure to secondhand smoke in workplaces, public spaces and on the property adjacent to public buildings.^1,2 In response, Canadian health authorities and hospitals began implementing policies mandating smoke-free hospital property, with the goals of reducing the exposure of workers, patients and visitors to tobacco smoke while delivering a public health message about the dangers of smoking.^2–5 An additional anticipated outcome was the reduced use of tobacco among patients and staff. The impetuses for adopting smoke-free policies include public support for such legislation and the potential for litigation for exposure to second-hand smoke.^2,4Tobacco use is a modifiable risk factor associated with a variety of cancers, cardiovascular diseases and respiratory conditions.^6–11 Patients in hospital who use tobacco tend to have more surgical complications and exacerbations of acute and chronic health conditions than patients who do not use tobacco.^6–11 Any policy aimed at reducing exposure to tobacco in hospitals is well supported by evidence, as is the integration of interventions targetting tobacco dependence.¹² Unfortunately, most of the nearly five million Canadians who smoke will receive suboptimal treatment,¹³ as the routine provision of interventions for tobacco dependence in hospital settings is not a practice norm.^14–16 In smoke-free hospitals, two studies suggest minimal support is offered for withdrawal, ^17,18 and one reports an increased use of nicotine-replacement therapy after the implementation of the smoke-free policy.¹⁹Assessments of the effectiveness of smoke-free policies for hospital property tend to focus on noncompliance and related issues of enforcement.^17,20,21 Although evidence of noncompliance and litter on hospital property^2,17,20 implies ongoing exposure to tobacco smoke, half of the participating hospital sites in one study reported less exposure to tobacco smoke within hospital buildings and on the property.¹⁸ In addition, there is evidence to suggest some decline in smoking among staff.^18,19,21,22We sought to determine the consequences of policies mandating smoke-free hospital property in two Canadian acute-care hospitals by eliciting lived experiences of the people faced with enacting the policies: patients and health care providers. In addition, we elicited stories from hospital support staff and administrators regarding the policies.     

Effect of a collaborative interdisciplinary maternity care program on perinatal outcomes

Background:

The number of physicians providing maternity care in Canada is decreasing, and the rate of cesarean delivery is increasing. We evaluated the effect on perinatal outcomes of an interdisciplinary program designed to promote physiologic birth and encourage active involvement of women and their families in maternity care.

Methods:

We conducted a retrospective cohort study involving 1238 women who attended the South Community Birth Program in Vancouver, Canada, from April 2004 to October 2010. The program offers comprehensive, collaborative, interdisciplinary care from family physicians, midwives, community health nurses and doulas to a multiethnic, low-income population. A comparison group, matched for neighbourhood of residence, maternal age, parity and gestational age at delivery, comprised 1238 women receiving standard care in community-based family physician, obstetrician and midwife practices. The primary outcome was the proportion of women who underwent cesarean delivery.

Results:

Compared with women receiving standard care, those in the birth program were more likely to be delivered by a midwife (41.9% v. 7.4%, p < 0.001) instead of an obstetrician (35.5% v. 69.6%, p < 0.001). The program participants were less likely than the matched controls to undergo cesarean delivery (relative risk [RR] 0.76, 95% confidence interval [CI] 0.68–0.84) and, among those with a previous cesarean delivery, more likely to plan a vaginal birth (RR 3.22, 95% CI 2.25–4.62). Length of stay in hospital was shorter in the program group for both the mothers (mean ± standard deviation 50.6 ± 47.1 v. 72.7 ± 66.7 h, p < 0.001) and the newborns (47.5 ± 92.6 v. 70.6 ± 126.7 h, p < 0.001). Women in the birth program were more likely than the matched controls to be breastfeeding exclusively at discharge (RR 2.10, 95% CI 1.85–2.39).

Interpretation:

Women attending a collaborative program of interdisciplinary maternity care were less likely to have a cesarean delivery, had shorter hospital stays on average and were more likely to breastfeed exclusively than women receiving standard care.In the last 2 decades, Canada has seen a dramatic reduction in the number of physicians providing maternity care.^1,2 Reasons for this decline have included liability concerns, lifestyle issues and perceived competence.³ A large proportion of obstetricians and family physicians who practise maternity care will reach retirement age in the next 10 years.⁴ The reduction in maternity care providers has been linked with hospital closures in rural settings and increasing difficulty in accessing obstetric care for women in all settings.⁴ Although the introduction of regulated midwifery promises some relief, midwives currently attend less than 10% of births.⁵Recent times have also seen a dramatic increase in the rates of interventions during childbirth, particularly cesarean delivery, which has risen from 17% in the 1990s to 28% in 2009 in Canada.⁶ This increase has occurred despite a lack of evidence that maternal and neonatal outcomes are improved with cesarean delivery.^7–10 Increasing rates of surgical delivery have placed an added burden on care provider resources, because of the associated intrapartum and postpartum complications¹¹ and increased length of stay in hospital.¹²In addition, increasing diversity, especially in urban settings, has made the delivery of maternity care more challenging. In the province of British Columbia, 16% of the population speaks neither official language at home.¹³ This proportion is as high as 32% in Vancouver, the province’s largest city and the setting of our study. There is evidence that immigrant women are at increased risk of receiving obstetric interventions and less likely to breastfeed.^14,15In response to these issues, the South Community Birth Program was established to provide comprehensive, collaborative maternity care from family physicians, midwives, community health nurses and doulas to a multiethnic, low-income population. The program aims to promote physiologic birth while encouraging women and their families to assume an active role in their maternity care. In the current study, we evaluated the impact of the program on perinatal outcomes.     

Maternal selenium status during early gestation and risk for preterm birth

Background

Preterm birth occurs in 5%–13% of pregnancies. It is a leading cause of perinatal mortality and morbidity and has adverse long-term consequences for the health of the child. Because of the role selenium plays in attenuating inflammation, and because low concentrations of selenium have been found in women with preeclampsia, we hypothesized that low maternal selenium status during early gestation would increase the risk of preterm birth.

Methods

White Dutch women with a singleton pregnancy (n = 1197) were followed prospectively from 12 weeks’ gestation. Women with thyroid disease or type 1 diabetes were excluded. At delivery, 1129 women had complete birth-outcome data. Serum concentrations of selenium were measured during the 12th week of pregnancy. Deliveries were classified as preterm or term, and preterm births were subcategorized as iatrogenic, spontaneous or the result of premature rupture of the membranes.

Results

Of the 60 women (5.3%) who had a preterm birth, 21 had premature rupture of the membranes and 13 had preeclampsia. The serum selenium concentration at 12 weeks’ gestation was significantly lower among women who had a preterm birth than among those who delivered at term (mean 0.96 [standard deviation (SD) 0.14] μmol/L v. 1.02 [SD 0.13] μmol/L; t = 2.9, p = 0.001). Women were grouped by quartile of serum selenium concentration at 12 weeks’ gestation. The number of women who had a preterm birth significantly differed by quartile (χ² = 8.01, 3 degrees of freedom], p < 0.05). Women in the lowest quartile of serum selenium had twice the risk of preterm birth as women in the upper three quartiles, even after adjustment for the occurrence of preeclampsia (adjusted odds ratio 2.18, 95% confidence interval 1.25–3.77).

Interpretation

Having low serum selenium at the end of the first trimester was related to preterm birth and was independent of the mother having preeclampsia. Low maternal selenium status during early gestation may increase the risk of preterm premature rupture of the membranes, which is a major cause of preterm birth.Preterm birth occurs in 5%–13% of pregnancies and is a major public health concern worldwide.¹ Preterm birth, defined as delivery before 37 weeks’ gestation, is the leading cause of perinatal mortality and morbidity.² Short- and long-term consequences to the health of the child include cerebral palsy, respiratory distress syndrome, neurodevelopmental impairment, learning difficulties and behavioural problems.² Despite substantial efforts to explain the mechanisms involved, the incidence of preterm birth is on the rise. For example, in the United States, the incidence increased from 9.5% in 1981 to 12.7% in 2005.¹ Consequently, it is important to identify factors that may contribute to preterm birth, particularly those factors that are preventable.Maternal risk factors for preterm birth include a previous preterm delivery, black race, low socioeconomic status, poor nutrition or becoming pregnant soon after a previous delivery.¹ Risk factors for preterm birth during gestation include multiple-gestation pregnancy and an intrauterine infection that triggers an inflammatory response.^1,3 Endocrine conditions such as diabetes and dysfunction of the thyroid have also been associated with preterm birth, sometimes linked to preterm premature rupture of the membranes.^4,5The trace mineral selenium, available from food (though to a greater or lesser extent according to region), can interact with a number of these risk factors.^6–9 It has been implicated in pregnancy outcome,^9–12 and it plays a role in the immune response and the body’s resistance to infection.⁶ Enzymes containing the mineral, selenoenzymes, can attenuate the excessive inflammatory response associated with adverse pregnancy outcomes, downregulating the expression of pro-inflammatory genes.^6–8 A polymorphism in the gene encoding the selenoprotein SEPS1 has been shown to affect the risk of preeclampsia, a condition that has a strong inflammatory component that is an important cause of preterm birth.⁸ In addition, low selenium status has been identified in women with preeclampsia.¹²We hypothesized that low maternal selenium status (as measured by low serum selenium concentration early in gestation would be associated with preterm birth. Previous small studies have compared plasma selenium and plasma/erythrocyte glutathione peroxidase in mothers and their babies during both term and preterm deliveries. Although lower values have often been found in mothers who had their babies preterm than in mothers who had their babies at term, the findings were inconsistent.^13–15 We did a prospective study to assess selenium status in a large cohort of pregnant women who were followed from early gestation to delivery.     

Risk of adverse outcomes among infants of immigrant women according to birth-weight curves tailored to maternal world region of origin

Background:Infants of immigrant women in Western nations generally have lower birth weights than infants of native-born women. Whether this difference is physiologic or pathological is unclear. We determined whether the use of birth-weight curves tailored to maternal world region of origin would discriminate adverse neonatal and obstetric outcomes more accurately than a single birth-weight curve based on infants of Canadian-born women.Methods:We performed a retrospective cohort study of in-hospital singleton live births (328 387 to immigrant women, 761 260 to nonimmigrant women) in Ontario between 2002 and 2012 using population health services data linked to the national immigration database. We classified infants as small for gestational age (< 10th percentile) or large for gestational age (≥ 90th percentile) using both Canadian and world region–specific birth-weight curves and compared associations with adverse neonatal and obstetric outcomes.Results:Compared with world region–specific birth-weight curves, the Canadian curve classified 20 431 (6.2%) additional newborns of immigrant women as small for gestational age, of whom 15 467 (75.7%) were of East or South Asian descent. The odds of neonatal death were lower among small-for-gestational-age infants of immigrant women than among those of nonimmigrant women based on the Canadian birth-weight curve (adjusted odds ratio [OR] 0.83, 95% confidence interval [CI] 0.72–0.95), but higher when small for gestational age was defined by the world region–specific curves (adjusted OR 1.24, 95% CI 1.08–1.42). Conversely, the odds of some adverse outcomes were lower among large-for-gestational-age infants of immigrant women than among those of nonimmigrant women based on world region–specific birth-weight curves, but were similar based on the Canadian curve.Interpretation:World region–specific birth-weight curves seemed to be more appropriate than a single Canadian population-based curve for assessing the risk of adverse neonatal and obstetric outcomes among small- and large-for-gestational-age infants born to immigrant women, especially those from the East and South Asian regions.In many Western nations, an increasing proportion of births are to immigrant women, many from world regions where low birth weight and infant death are more frequent.^1–3 The birth-weight distribution of infants born to immigrant mothers in Canada and the United Kingdom is shifted toward lower birth-weight values than that of infants born to native-born women.^4,5 Accordingly, use of a conventional population-based birth-weight chart may not be appropriate for all immigrant groups, potentially leading to an overestimation of infants as small for gestational age (birth weight < 10th percentile) and an underestimation of infants as large for gestational age (birth weight ≥ 90th percentile). The question remains whether these differences reflect a physiologic or a pathological process.Potentially misclassifying the physiologically small, but healthy, newborn as small for gestational age may lead to unnecessary interventions and undue parental stress.⁶ To date, comparisons between a single population-based standard and customized standards, including ones that are based on ethnicity, have focused on small-for-gestational-age infants, but less attention has been paid to the potential under-classification of large infants.^7–9 Overlooking a fetus or infant who would be considered large for gestational age according to the birth-weight distribution in his mother’s country of origin, but not according to the higher cut-off of a birth-weight curve for infants of Canadian-born women, may fail to identify a higher risk of birth trauma or obstetric complications, such as perineal laceration, shoulder dystocia and postpartum hemorrhage.^10–12To date, there is no consensus regarding the minimal set of maternal characteristics that improves detection of adverse outcomes through the use of customized charts.^13–17 So far, the single characteristic that has been shown to influence the size of newborns in this way is maternal country of birth.¹⁸We conducted a study to determine whether use of world region–specific birth-weight curves would be more accurate than use of a single birth-weight curve based on infants of Canadian-born women in predicting adverse neonatal and obstetric outcomes known to be associated with small for gestational age and large for gestational age among infants born to immigrant women in Canada.     

Risk of vascular events in patients with polymyalgia rheumatica

Background:

Polymyalgia rheumatica is one of the most common inflammatory rheumatologic conditions in older adults. Other inflammatory rheumatologic disorders are associated with an excess risk of vascular disease. We investigated whether polymyalgia rheumatica is associated with an increased risk of vascular events.

Methods:

We used the General Practice Research Database to identify patients with a diagnosis of incident polymyalgia rheumatica between Jan. 1, 1987, and Dec. 31, 1999. Patients were matched by age, sex and practice with up to 5 patients without polymyalgia rheumatica. Patients were followed until their first vascular event (cardiovascular, cerebrovascular, peripheral vascular) or the end of available records (May 2011). All participants were free of vascular disease before the diagnosis of polymyalgia rheumatica (or matched date). We used Cox regression models to compare time to first vascular event in patients with and without polymyalgia rheumatica.

Results:

A total of 3249 patients with polymyalgia rheumatica and 12 735 patients without were included in the final sample. Over a median follow-up period of 7.8 (interquartile range 3.3–12.4) years, the rate of vascular events was higher among patients with polymyalgia rheumatica than among those without (36.1 v. 12.2 per 1000 person-years; adjusted hazard ratio 2.6, 95% confidence interval 2.4–2.9). The increased risk of a vascular event was similar for each vascular disease end point. The magnitude of risk was higher in early disease and in patients younger than 60 years at diagnosis.

Interpretation:

Patients with polymyalgia rheumatica have an increased risk of vascular events. This risk is greatest in the youngest age groups. As with other forms of inflammatory arthritis, patients with polymyalgia rheumatica should have their vascular risk factors identified and actively managed to reduce this excess risk.Inflammatory rheumatologic disorders such as rheumatoid arthritis,^1,2 systemic lupus erythematosus,^2,3 gout,⁴ psoriatic arthritis^2,5 and ankylosing spondylitis^2,6 are associated with an increased risk of vascular disease, especially cardiovascular disease, leading to substantial morbidity and premature death.^2–6 Recognition of this excess vascular risk has led to management guidelines advocating screening for and management of vascular risk factors.^7–9Polymyalgia rheumatica is one of the most common inflammatory rheumatologic conditions in older adults,¹⁰ with a lifetime risk of 2.4% for women and 1.7% for men.¹¹ To date, evidence regarding the risk of vascular disease in patients with polymyalgia rheumatica is unclear. There are a number of biologically plausible mechanisms between polymyalgia rheumatica and vascular disease. These include the inflammatory burden of the disease,^12,13 the association of the disease with giant cell arteritis (causing an inflammatory vasculopathy, which may lead to subclinical arteritis, stenosis or aneurysms),¹⁴ and the adverse effects of long-term corticosteroid treatment (e.g., diabetes, hypertension and dyslipidemia).^15,16 Paradoxically, however, use of corticosteroids in patients with polymyalgia rheumatica may actually decrease vascular risk by controlling inflammation.¹⁷ A recent systematic review concluded that although some evidence exists to support an association between vascular disease and polymyalgia rheumatica,¹⁸ the existing literature presents conflicting results, with some studies reporting an excess risk of vascular disease^19,20 and vascular death,^21,22 and others reporting no association.^23–26 Most current studies are limited by poor methodologic quality and small samples, and are based on secondary care cohorts, who may have more severe disease, yet most patients with polymyalgia rheumatica receive treatment exclusively in primary care.²⁷The General Practice Research Database (GPRD), based in the United Kingdom, is a large electronic system for primary care records. It has been used as a data source for previous studies,²⁸ including studies on the association of inflammatory conditions with vascular disease²⁹ and on the epidemiology of polymyalgia rheumatica in the UK.³⁰ The aim of the current study was to examine the association between polymyalgia rheumatica and vascular disease in a primary care population.     

Reasons for cannabis use during pregnancy and lactation: a qualitative study

Background:Cannabis use among pregnant and lactating people is increasing, despite clinical evidence showing that cannabis use may be associated with low birth weight and childhood developmental deficits. Our objective was to understand why pregnant and lactating people use cannabis and how these motivations change across perinatal stages.Methods:Using qualitative, constructivist grounded theory methodology, we conducted telephone and virtual interviews with 52 individuals from across Canada. We selected participants using maximum variation and theoretical sampling. They were eligible if they had been pregnant or lactating within the past year and had decided to continue, cease or decrease their cannabis use during the perinatal period.Results:We identified 3 categories of reasons that people use cannabis during pregnancy and lactation: sensation-seeking for fun and enjoyment; symptom management of chronic conditions and conditions related to pregnancy; and coping with the unpleasant, but nonpathologized, experiences of life. Before pregnancy, participants endorsed reasons for using cannabis in these 3 categories in similar proportions, with many offering multiple reasons for use. During pregnancy, reasons for use shifted primarily to symptom management. During lactation, reasons returned to resemble those expressed before pregnancy.Interpretation:In this study, we showed that pregnant and lactating people use cannabis for many reasons, particularly for symptom management. Reasons for cannabis use changed across reproductive stages. The dynamic nature of the reasons for use across stages speaks to participant perception of benefits and risks, and perhaps a desire to cast cannabis use during pregnancy as therapeutic because of perceived stigma.

Cannabis use by pregnant and lactating people is increasing, though it is difficult to establish the prevalence of cannabis use in pregnancy. Reported prevalence varies from 2% to 36%, depending on the methodology used to detect use, the population studied and the definition of use.^1–12 Pregnant people have reported using cannabis to manage pregnancy-related conditions (e.g., nausea, weight gain, sleep difficulty)^13–19 and pre-existing conditions (e.g., mental health, insomnia, chronic pain),^13,14,18 as well as to improve mood, mental, physical and spiritual well-being,^16,18 provide pleasure and manage stress.^13–16 Recent systematic reviews have not found empirical data on reasons for cannabis use during lactation.^20,21Evidence is still emerging about clinical outcomes related to cannabis use during pregnancy and lactation, and well-controlled studies are lacking.^22–24 The available evidence is limited by reliance on self-reported data about dose, composition and timing of exposure, the changing nature of tetrahydrocannabinol levels in cannabis over time, and a lack of studies that control for known confounders such as polysubstance and tobacco use.^25–31 The available evidence does suggest that cannabis use during pregnancy may be associated with complications such as low birth weight, childhood neurodevelopmental outcomes and preterm birth.^{22–24,32,33} Very few studies have analyzed the outcomes associated with cannabis exposure through breastmilk, with 1 study suggesting decreased infant motor development and another showing no effects on developmental outcomes.^34–36 Given the potential harms identified, and in the absence of high-quality evidence available to guide practice, most clinical guidelines recommend abstinence from cannabis during pregnancy and lactation.^37–39People who perceive benefits from cannabis may wish to or may be motivated to continue using it through pregnancy and lactation, however. Counselling that explores the reasons patients are considering cannabis use and suggests related alternatives or harm reduction strategies has been identified as a helpful strategy to minimize potential harm.^13,40,41,42 Such an approach requires that clinicians understand the motivations to use cannabis before pregnancy, during pregnancy and during lactation. We sought to explore why people use cannabis during pregnancy and lactation.