Perinatal mortality and adverse pregnancy outcomes in a low‐income rural population of women who smoke

We describe adverse pregnancy outcomes, including congenital anomalies, fetal, neonatal, and infant mortality among a Missouri population of low‐income, rural mothers who participated in two randomized smoking cessation trials. In the Baby BEEP (BB) trial, 695 rural women were recruited from 21 WIC clinics with 650 women's pregnancy outcomes known (93.5% retention rate). Following the BB trial, 298 women who had a live infant after November 2004 were recruited again into and completed the Baby Beep for Kids (BBK) trial. Simple statistics describing the population and perinatal and postneonatal mortality rates were calculated. Of the adverse pregnancy outcomes (n = 79), 29% were spontaneous abortions of less than 20 weeks' gestation, 23% were premature births, and 49% were identified birth defects. The perinatal mortality rate was 15.9 per 1000 births (BB study) compared with 8.6 per 1000 births (state of Missouri) and 8.5 per 1000 births (United States). The postneonatal infant mortality rate was 13.4 per 1000 live births (BBK) compared with 2.1 per 1000 live births (United States). The health disparity in this population of impoverished, rural, pregnant women who smoke, particularly in regard to perinatal and infant deaths, warrants attention. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.     

Perinatal mortality and adverse pregnancy outcomes in a low-income rural population of women who smoke

We describe adverse pregnancy outcomes, including congenital anomalies, fetal, neonatal, and infant mortality among a Missouri population of low-income, rural mothers who participated in two randomized smoking cessation trials. In the Baby BEEP (BB) trial, 695 rural women were recruited from 21 WIC clinics with 650 women's pregnancy outcomes known (93.5% retention rate). Following the BB trial, 298 women who had a live infant after November 2004 were recruited again into and completed the Baby Beep for Kids (BBK) trial. Simple statistics describing the population and perinatal and postneonatal mortality rates were calculated. Of the adverse pregnancy outcomes (n = 79), 29% were spontaneous abortions of less than 20 weeks' gestation, 23% were premature births, and 49% were identified birth defects. The perinatal mortality rate was 15.9 per 1000 births (BB study) compared with 8.6 per 1000 births (state of Missouri) and 8.5 per 1000 births (United States). The postneonatal infant mortality rate was 13.4 per 1000 live births (BBK) compared with 2.1 per 1000 live births (United States). The health disparity in this population of impoverished, rural, pregnant women who smoke, particularly in regard to perinatal and infant deaths, warrants attention.     

Evaluation of preterm births and birth defects in liveborn infants of US military women who received smallpox vaccine

BACKGROUND: Women serving in the US military have some unique occupational exposures, including exposure to vaccinations that are rarely required in civilian professions. When vaccinations are inadvertently given during pregnancy, such exposures raise special concerns. These analyses address health outcomes, particularly preterm births and birth defects, among infants who appear to have been exposed to maternal smallpox vaccination in pregnancy. METHODS: This retrospective cohort study included 31,420 infants born to active‐duty military women during 2003–2004. We used Department of Defense databases to define maternal vaccination and infant health outcomes. Multivariable regression models were developed to describe associations between maternal smallpox vaccination and preterm births and birth defects in liveborn infants. RESULTS: There were 7,735 infants identified as born to women ever vaccinated against smallpox, and 672 infants born to women vaccinated in the first trimester of pregnancy. In multivariable modeling, maternal smallpox vaccination in pregnancy was not associated with preterm or extreme preterm delivery. Maternal smallpox vaccination in the first trimester of pregnancy was not significantly associated with overall birth defects (OR 1.40; 95% CI: 0.94, 2.07), or any of seven specific defects individually modeled. CONCLUSIONS: Results may be reassuring that smallpox vaccine, when inadvertently administered to pregnant women, is not associated with preterm delivery or birth defects in liveborn infants. Birth Defects Research (Part A) 2008. © 2008 Wiley‐Liss, Inc.     

Change in social status and risk of low birth weight in Denmark: population based cohort study.

OBJECTIVE: To estimate the risk of having a low birthweight infant associated with changes in social, environmental, and genetic factors. DESIGN: Population based, historical cohort study using the Danish medical birth registry and Statistic Denmark''s fertility database. SUBJECTS: All women who had a low birthweight infant (< 2500 g) (index birth) and a subsequent liveborn infant (outcome birth) in Denmark between 1980 and 1992 (exposed cohort, n = 11,069) and a random sample of the population who gave birth to an infant weighing > or = 2500 g and to a subsequent liveborn infant (unexposed cohort, n = 10,211). MAIN OUTCOME MEASURES: Risk of having a low birthweight infant in the outcome birth as a function of changes in male partner, area of residence, type of job, and social status between the two births. RESULTS: Women in the exposed cohort showed a high risk (18.5%) of having a subsequent low birthweight infant while women in the unexposed cohort had a risk of 2.8%. After adjustment for initial social status, a decline in social status increased the absolute risk of having a low birthweight infant by about 5% in both cohorts, though this was significant only in the unexposed cohort. Change of male partner did not modify the risk of low birth weight in either cohort. CONCLUSION: Having had a low birthweight infant and a decline in social status are strong risk factors for having a low birthweight infant subsequently.     

Interpregnancy interval and risk of preterm birth and neonatal death: retrospective cohort study

Objective To determine whether a short interval between pregnancies is an independent risk factor for adverse obstetric outcome.Design Retrospective cohort study.Setting Scotland.Subjects 89 143 women having second births in 1992-8 who conceived within five years of their first birth.Main outcome measures Intrauterine growth restriction (birth weight less than the 5th centile for gestational age), extremely preterm birth (24-32 weeks), moderately preterm birth (33-36 weeks), and perinatal death.Results Women whose subsequent interpregnancy interval was less than six months were more likely than other women to have had a first birth complicated by intrauterine growth restriction (odds ratio 1.3, 95% confidence interval 1.1 to 1.5), extremely preterm birth (4.1, 3.2 to 5.3), moderately preterm birth (1.5, 1.3 to 1.7), or perinatal death (24.4, 18.9 to 31.5). They were also shorter, less likely to be married, and more likely to be aged less than 20 years at the time of the second birth, to smoke, and to live in an area of high socioeconomic deprivation. When the outcome of the second birth was analysed in relation to the preceding interpregnancy interval and the analysis confined to women whose first birth was a term live birth (n = 69 055), no significant association occurred (adjusted for age, marital status, height, socioeconomic deprivation, smoking, previous birth weight vigesimal, and previous caesarean delivery) between interpregnancy interval and intrauterine growth restriction or stillbirth. However, a short interpregnancy interval (< 6 months) was an independent risk factor for extremely preterm birth (adjusted odds ratio 2.2, 1.3 to 3.6), moderately preterm birth (1.6, 1.3 to 2.0), and neonatal death unrelated to congenital abnormality (3.6, 1.2 to 10.7). The adjusted attributable fractions for these associations were 6.1%, 3.9%, and 13.8%. The associations were very similar when the analysis was confined to married non-smokers aged 25 and above.Conclusions A short interpregnancy interval is an independent risk factor for preterm delivery and neonatal death in the second birth.     

The Associations between Bridal Pregnancy and Obstetric Outcomes among Live Births in Korea: Population-Based Study

Objective

In East Asia the recently increased number of marriages in response to pregnancy is an important social issue. This study evaluated the association of marriage preceded by pregnancy (bridal pregnancy) with obstetric outcomes among live births in Korea.

Methods

In this population-based study, 1,152,593 first singleton births were evaluated from data registered in the national birth registration database from 2004 to 2008 in Korea. In the study population, the pregnancy outcomes among live births from the bridal pregnancy group (N = 62,590) were compared with the outcomes of the post-marital pregnancy group (N = 564,749), composed of women who gave birth after 10 months but before 24 months of marriage. The variables preterm birth (PTB; <37 weeks gestation) and low birth weight (LBW; <2.5 kg) were used to determine the primary outcome. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated after controlling for socio-demographic factors.

Results

The socio-demographic factors among the bridal pregnancy group were associated with a social disadvantage and particular risk factors. In the subgroup analyses of maternal age, differences in adverse pregnancy outcomes from bridal pregnancy were identified between women in the following age group: (i) ≤19, (ii) 20–39, and (iii) ≥40 years. After the multivariate analysis, the aORs for each age group were 1.47 (95% CI: 1.15–1.89), 1.76 (1.70–1.83), and 1.13 (0.77–1.66), respectively, for PTB and 0.92 (0.70–1.21), 1.60 (1.53–1.66), and 1.11 (0.71–1.74), respectively, for LBW. In the adjusted logistic regression models, bridal pregnancy was associated with PTB (1.76, 1.69–1.82) and LBW (1.53, 1.48–1.59).

Conclusion

Pregnancy outcomes among live births from bridal pregnancies are associated with higher risks for PTB and LBW in Korea.     

Demographic and socioeconomic determinants of low birth weight and preterm births among natives and immigrants in Greece: an analysis using nationwide vital registration micro-data

The present study makes use of nationwide individual-level vital registration data on the single live births occurring in Greece in 2006 to explore associations of socio-demographic factors with adverse pregnancy outcomes, using multinomial logistic regression models. The findings indicate that important risk factors associated with low birth weight preterm and intra-uterine growth retarded births (IUGR) include female sex, primiparity, age of mother over 35, illegitimacy and prior history of stillbirths, infant and child deaths. These constitute risk factors for normal weight preterm births as well, though associations with sex and primiparity in this case point to the opposite direction. Residing in large metropolitan areas is related to a greater risk of an IUGR birth. Among Greek women, educational attainment has a protective effect while housewife status is linked to higher chances of an IUGR birth. For immigrant mothers however, the opposite holds. The study also shows that normal weight preterm births form a distinct group.     

Risk Assessment of Adverse Birth Outcomes in Relation to Maternal Age

Background

Although a number of studies have investigated correlations of maternal age with birth outcomes, an extensive assessment using age as a continuous variable is lacking. In the current study, we estimated age-specific risks of adverse birth outcomes in childbearing women.

Method

National population-based data containing maternal and neonatal information were derived from the Health Promotion Administration, Taiwan. A composite adverse birth outcome was defined as at least anyone of stillbirth, preterm birth, low birth weight, macrosomia, neonatal death, congenital anomaly, and small for gestational age (SGA). Singletons were further analyzed for outcomes of live birth in relation to each year of maternal age. A log-binomial model was used to adjust for possible confounders of maternal and neonatal factors.

Results

In total, 2,123,751 births between 2001 and 2010 were utilized in the analysis. The risk of a composite adverse birth outcome was significantly higher at extreme maternal ages. In specific, risks of stillbirth, neonatal death, preterm birth, congenital anomaly, and low birth weight were higher at the extremes of maternal age. Furthermore, risk of macrosomia rose proportionally with an increasing maternal age. In contrast, risk of SGA declined proportionally with an increasing maternal age. The log-binomial model showed greater risks at the maternal ages of <26 and > 30 years for a composite adverse birth outcome.

Conclusions

Infants born to teenagers and women at advanced age possess greater risks for stillbirth, preterm birth, neonatal death, congenital anomaly, and low birth weight. Pregnancies at advanced age carry an additional risk for macrosomia, while teenage pregnancies carry an additional risk for SGA. The data suggest that the optimal maternal ages to minimize adverse birth outcomes are 26∼30 years.     

Disparities and Trends in Birth Outcomes,Perinatal and Infant Mortality in Aboriginal vs. Non-Aboriginal Populations: A Population-Based Study in Quebec,Canada 1996–2010

Background

Aboriginal populations are at substantially higher risks of adverse birth outcomes, perinatal and infant mortality than their non-Aboriginal counterparts even in developed countries including Australia, U.S. and Canada. There is a lack of data on recent trends in Canada.

Methods

We conducted a population-based retrospective cohort study (n = 254,410) using the linked vital events registry databases for singleton births in Quebec 1996–2010. Aboriginal (First Nations, Inuit) births were identified by mother tongue, place of residence and Indian Registration System membership. Outcomes included preterm birth, small-for-gestational-age, large-for-gestational-age, low birth weight, high birth weight, stillbirth, neonatal death, postneonatal death, perinatal death and infant death.

Results

Perinatal and infant mortality rates were 1.47 and 1.80 times higher in First Nations (10.1 and 7.3 per 1000, respectively), and 2.37 and 4.46 times higher in Inuit (16.3 and 18.1 per 1000, respectively) relative to non-Aboriginal (6.9 and 4.1 per 1000, respectively) births (all p<0.001). Compared to non-Aboriginal births, preterm birth rates were persistently (1.7–1.8 times) higher in Inuit, large-for-gestational-age birth rates were persistently (2.7–3.0 times) higher in First Nations births over the study period. Between 1996–2000 and 2006–2010, as compared to non-Aboriginal infants, the relative risk disparities increased for infant mortality (from 4.10 to 5.19 times) in Inuit, and for postneonatal mortality in Inuit (from 6.97 to 12.33 times) or First Nations (from 3.76 to 4.25 times) infants. Adjusting for maternal characteristics (age, marital status, parity, education and rural vs. urban residence) attenuated the risk differences, but significantly elevated risks remained in both Inuit and First Nations births for the risks of perinatal mortality (1.70 and 1.28 times, respectively), infant mortality (3.66 and 1.47 times, respectively) and postneonatal mortality (6.01 and 2.28 times, respectively) in Inuit and First Nations infants (all p<0.001).

Conclusions

Aboriginal vs. non-Aboriginal disparities in adverse birth outcomes, perinatal and infant mortality are persistent or worsening over the recent decade in Quebec, strongly suggesting the needs for interventions to improve perinatal and infant health in Aboriginal populations, and for monitoring the trends in other regions in Canada.     

The COVID-19 pandemic and birth outcomes in 2020: The role of prenatal care and other channels

We use national birth data to assess the associations between the COVID-19 pandemic during 2020 and birth outcomes in Uruguay. Employing interrupted time series difference-in-differences techniques, we find mixed results, with some pregnancies showing increases in the likelihood of very preterm or very-low-weight births, and some others showing decreases in the incidence of moderate prematurity and moderate low birth weight. Adverse outcomes are more likely among women with low education, women with previous children, and with risk factors, such as smoking or being older than 34. We observe improvements in health at birth for children of non-smokers, women younger than 35, and women with no other children. We underscore the role of health care by showing that women in the private sector, who suffered the strongest contraction in face-to-face prenatal care use, experienced more adverse birth outcomes. Our results also suggest that the economic recession and an increased burden of childcare were behind the increases in preterm and very-low-weight births. Because pollution is an unlikely channel for the positive results, we hypothesize that for some pregnancies, the pandemic improved the intrauterine habitat by leading to a quieter and healthier lifestyle.     

Inflammatory Bowel Disease and Risk of Adverse Pregnancy Outcomes

Background and Objectives

Existing data on pregnancy complications in inflammatory bowel disease (IBD) are inconsistent. To address these inconsistencies, we investigated potential associations between IBD, IBD-related medication use during pregnancy, and pregnancy loss, pre-eclampsia, preterm delivery, Apgar score, and congenital abnormalities.

Methods

We conducted a cohort study in >85,000 Danish National Birth Cohort women who were pregnant in the period 1996-2002 and had information on IBD, IBD-related medication use (systemic or local corticosteroids, 5-aminosalicylates), pregnancy outcomes and potential confounders. We evaluated associations between IBD and adverse pregnancy/birth outcomes using Cox regression and log-linear binomial regression.

Results

IBD was strongly and significantly associated with severe pre-eclampsia, preterm premature rupture of membranes and medically indicated preterm delivery in women using systemic corticosteroids during pregnancy (hazard ratios [HRs] >7). IBD was also associated with premature preterm rupture of membranes in women using local corticosteroid medications (HR 3.30, 95% confidence interval [CI] 1.33-8.20) and with medically indicated preterm delivery (HR 1.91, 95% CI 0.99-3.68) in non-medicated women. Furthermore, IBD was associated with low 5-minute Apgar score in term infants (risk ratio [RR] 2.19, 95% CI 1.03-4.66). Finally, Crohn’s disease (but not ulcerative colitis) was associated with major congenital abnormalities in the offspring (RR 1.85, 95% CI 1.06-3.21). No child with a congenital abnormality born to a woman with IBD was exposed to systemic corticosteroids in utero.

Conclusion

Women with IBD are at increased risk of severe pre-eclampsia, medically indicated preterm delivery, preterm premature rupture of membranes, and delivering infants with low Apgar score and major congenital malformations. These associations are only partly explained by severe disease as reflected by systemic corticosteroid use.     

Preterm Birth Prevention Post-Conization: A Model of Cervical Length Screening with Targeted Cerclage

Women with a history of excisional treatment (conization) for cervical intra-epithelial neoplasia (CIN) are at increased risk of preterm birth, perinatal morbidity and mortality in subsequent pregnancy. We aimed to develop a screening model to effectively differentiate pregnancies post-conization into low- and high-risk for preterm birth, and to evaluate the impact of suture material on the efficacy of ultrasound indicated cervical cerclage. We analysed longitudinal cervical length (CL) data from 725 pregnant women post-conization attending preterm surveillance clinics at three London university Hospitals over a ten year period (2004–2014). Rates of preterm birth <37 weeks after targeted cerclage for CL<25mm were compared with local and national background rates and expected rates for this cohort. Rates for cerclage using monofilament or braided suture material were also compared. Of 725 women post-conization 13.5% (98/725) received an ultrasound indicated cerclage and 9.7% (70/725) delivered prematurely, <37weeks; 24.5% (24/98) of these despite insertion of cerclage. The preterm birth rate was lower for those that had monofilament (9/60, 15%) versus braided (15/38, 40%) cerclage (RR 0.7, 95% CI 0.54 to 0.94, P = 0.008). Accuracy parameters of interval reduction in CL between longitudinal second trimester screenings were calculated to identify women at low risk of preterm birth, who could safely discontinue surveillance. A reduction of CL <10% between screening timepoints predicts term birth, >37weeks. Our triage model enables timely discharge of low risk women, eliminating 36% of unnecessary follow-up CL scans. We demonstrate that preterm birth in women post-conization may be reduced by targeted cervical cerclage. Cerclage efficacy is however suture material-dependant: monofilament is preferable to braided suture. The introduction of triage prediction models has the potential to reduce the number of unnecessary CL scan for women at low risk of preterm birth.     

Operative vaginal delivery and neonatal and infant adverse outcomes: population based retrospective analysis

Objective To compare the risk of neonatal and infant adverse outcomes between vacuum and forceps assisted deliveries.Design Population based study.Setting US linked natality and mortality birth cohort file and the New Jersey linked natality, mortality, and hospital discharge summary birth cohort file.Participants Singleton live births in the United States (n = 11 639 388) and New Jersey (n = 375 351).Main outcome measures Neonatal morbidity and mortality.Results Neonatal mortality was comparable between vacuum and forceps deliveries in US births (odds ratio 0.94, 95% confidence interval 0.79 to 1.12). Vacuum delivery was associated with a lower risk of birth injuries (0.69, 0.66 to 0.72), neonatal seizures (0.78, 0.68 to 0.90), and need for assisted ventilation (< 30 minutes 0.94, 0.92 to 0.97; ≥ 30 minutes 0.92, 0.88 to 0.98). Among births in New Jersey, vacuum extraction was more likely than forceps to be complicated by postpartum haemorrhage (1.22, 1.07 to 1.39) and shoulder dystocia (2.00, 1.62 to 2.48). The risks of intracranial haemorrhage, difficulty with feeding, and retinal haemorrhage were comparable between both modes of delivery. The sequential use of vacuum and forceps was associated with an increased risk of need for mechanical ventilation in the infant and third and fourth degree perineal tears.Conclusion Although vacuum extraction does have risks, it remains a safe alternative to forceps delivery.     

Changes in Association between Previous Therapeutic Abortion and Preterm Birth in Scotland, 1980 to 2008: A Historical Cohort Study

Background

Numerous studies have demonstrated that therapeutic termination of pregnancy (abortion) is associated with an increased risk of subsequent preterm birth. However, the literature is inconsistent, and methods of abortion have changed dramatically over the last 30 years. We hypothesized that the association between previous abortion and the risk of preterm first birth changed in Scotland between 1 January 1980 and 31 December 2008.

Methods and Findings

We studied linked Scottish national databases of births and perinatal deaths. We analysed the risk of preterm birth in relation to the number of previous abortions in 732,719 first births (≥24 wk), adjusting for maternal characteristics. The risk (adjusted odds ratio [95% CI]) of preterm birth was modelled using logistic regression, and associations were expressed for a one-unit increase in the number of previous abortions. Previous abortion was associated with an increased risk of preterm birth (1.12 [1.09–1.16]). When analysed by year of delivery, the association was strongest in 1980–1983 (1.32 [1.21–1.43]), progressively declined between 1984 and 1999, and was no longer apparent in 2000–2003 (0.98 [0.91–1.05]) or 2004–2008 (1.02 [0.95–1.09]). A statistical test for interaction between previous abortion and year was highly statistically significant (p<0.001). Analysis of data for abortions among nulliparous women in Scotland 1992–2008 demonstrated that the proportion that were surgical without use of cervical pre-treatment decreased from 31% to 0.4%, and that the proportion of medical abortions increased from 18% to 68%.

Conclusions

Previous abortion was a risk factor for spontaneous preterm birth in Scotland in the 1980s and 1990s, but the association progressively weakened and disappeared altogether by 2000. These changes were paralleled by increasing use of medical abortion and cervical pre-treatment prior to surgical abortion. Although it is plausible that the two trends were related, we could not test this directly as the data on the method of prior abortions were not linked to individuals in the cohort. However, we speculate that modernising abortion methods may be an effective long-term strategy to reduce global rates of preterm birth. Please see later in the article for the Editors'' Summary     

Risk Factors and Birth Outcomes of Anaemia in Early Pregnancy in a Nulliparous Cohort

Background

Anaemia in pregnancy is a major public health and economic problem worldwide, that contributes to both maternal and fetal morbidity and mortality.

Objective

The aim of the study was to calculate the prevalence of anaemia in early pregnancy in a cohort of ‘low risk’ women participating in a large international multicentre prospective study (n = 5 609), to identify the modifiable risk factors for anaemia in pregnancy in this cohort, and to compare the birth outcomes between pregnancies with and without anaemia in early gestation.

Methods

The study is an analysis of data that were collected prospectively during the Screening for Pregnancy Endpoints study. Anaemia was defined according to the World Health Organization’s definition of anaemia in pregnancy (haemoglobin < 11g/dL). Binary logistic regression with adjustment for potential confounders (country, maternal age, having a marital partner, ethnic origin, years of schooling, and having paid work) was the main method of analysis.

Results

The hallmark findings were the low prevalence of anaemia (2.2%), that having no marital partner was an independent risk factor for having anaemia (OR 1.34, 95% CI 1.01-1.78), and that there was no statistically significant effect of anaemia on adverse pregnancy outcomes (small for gestational age, pre-tem birth, mode of delivery, low birth weight, APGAR score < 7 at one and five minutes). Adverse pregnancy outcomes were however more common in those with anaemia than in those without.

Conclusion

In this low risk healthy pregnant population we found a low anaemia rate. The absence of a marital partner was a non-modifiable factor, albeit one which may reflect a variety of confounding factors, that should be considered for addition to anaemia’s conceptual framework of determinants. Although not statistically significant, clinically, a trend towards a higher risk of adverse pregnancy outcomes was observed in women that were anaemic in early pregnancy.     

The Apgar Score and Infant Mortality

Objective

To evaluate if the Apgar score remains pertinent in contemporary practice after more than 50 years of wide use, and to assess the value of the Apgar score in predicting infant survival, expanding from the neonatal to the post-neonatal period.

Methods

The U.S. linked live birth and infant death dataset was used, which included 25,168,052 singleton births and 768,305 twin births. The outcome of interest was infant death within 1 year after birth. Cox proportional hazard-model was used to estimate risk ratio of infant mortality with different Apgar scores.

Results

Among births with a very low Apgar score at five minutes (1–3), the neonatal and post-neonatal mortality rates remained high until term (≥ 37 weeks). On the other hand, among births with a high Apgar score (≥7), neonatal and post-neonatal mortality rate decreased progressively with gestational age. Non-Hispanic White had a consistently higher neonatal mortality than non-Hispanic Black in both preterm and term births. However, for post-neonatal mortality, Black had significantly higher rate than White. The pattern of changes in neonatal and post-neonatal mortality by Apgar score in twin births is essentially the same as that in singleton births.

Conclusions

The Apgar score system has continuing value for predicting neonatal and post-neonatal adverse outcomes in term as well as preterm infants, and is applicable to twins and in various race/ethnic groups.     

Maternal and Neonatal Outcomes among Pregnant Women with 2009 Pandemic Influenza A(H1N1) Illness in Florida, 2009-2010: A Population-Based Cohort Study

Introduction

Pregnant women have been identified as a high risk group for severe illness with 2009 pandemic influenza A(H1N1) virus infection (pH1N1). Obesity has also been identified as a risk factor for severe illness, though this has not been thoroughly assessed among pregnant women. The objectives of this study were to provide risk estimates for adverse maternal and neonatal outcomes associated with pH1N1 illness during pregnancy and to assess the role of obesity in these outcomes.

Methods

We established a retrospective population-based cohort of all live births occurring in Florida during the first 15 months of the pandemic. Illness with pH1N1 during pregnancy was ascertained through record linkage with the Florida state notifiable disease surveillance database. Data from the birth record, including pre-pregnancy body mass index, were analyzed to assess risk of adverse outcomes associated with pH1N1 illness.

Results

A total of 194 women were identified through surveillance with pH1N1 illness during pregnancy. Children born to women with pH1N1 illness during pregnancy were at increased risk for low birth weight [OR (95%CI): 1.78 (1.11-2.860)], premature birth [2.21 (1.47-3.330)], and infant death [4.46 (1.80-11.00)], after adjusting for other factors. Women with pH1N1 illness during pregnancy were at increased risk for severe outcomes including admission to an intensive care unit. Obesity was an observed risk factor, both for the more severe pH1N1 illness detected through surveillance, and for severe maternal outcomes.

Conclusions

Case-patients in this analysis likely represent the most severely ill subset of all women infected with pH1N1 during pregnancy, limiting the generalizability of these findings to more severely ill patients rather than influenza infection in general. Nevertheless, these results suggest that more severe pH1N1 illness during pregnancy is associated with adverse neonatal outcomes and that pregnant women should continue to be targeted for appropriate prophylaxis and early treatment.     

Adequate Prenatal Care Reduces the Risk of Adverse Pregnancy Outcomes in Women with History of Infertility: A Nationwide Population-Based Study

Objectives

To investigate the effects of various measures of prenatal care on adverse pregnancy outcomes in women with a history of infertility.

Study Design

A retrospective cohort study.

Methods

Data were derived by linking 2 large nationwide population-based datasets, the National Health Insurance Research Database and Taiwan Birth Certificate Registry. The study sample included 15,056 women with an infertility diagnosis and 60,224 randomly selected women without infertility matched to the study sample by maternal age. A conditional logistic regression analysis was performed for the analysis.

Results

Women diagnosed with infertility respectively had 1.39 (95% CI, 1.06~1.83), 1.15 (95% CI, 1.08~1.24), 1.13 (95% CI, 1.08~1.18), and 1.08 (95% CI, 1.05~1.12) higher odds of having very low birth weight (VLBW) babies, preterm births, labor complications, and cesarean sections (CSs) compared to women without infertility. Inadequate numbers of total and major prenatal visits and late initiation of prenatal care increased the risks of adverse pregnancy outcomes in women with infertility, especially the risk of a VLBW baby. However, no significant associations were found for the risks of adverse birth outcomes in infertile women with adequate prenatal care compared to fertile women with adequate care.

Conclusions

Study findings suggest that adequate prenatal care can reduce the risk of adverse pregnancy outcomes in women with infertility.     

Maternal and Antenatal Risk Factors for Stillbirths and Neonatal Mortality in Rural Bangladesh: A Case-Control Study

Objective

To identify maternal and antenatal factors associated with stillbirths and neonatal deaths in rural Bangladesh.

Study Design

A prospective cohort study is being conducted to evaluate a maternal and child nutrition program in rural Bangladesh. Cases were all stillbirths and neonatal deaths that occurred in the cohort between March 7, 2011 and December 30, 2011. Verbal autopsies were used to determine cause of death. For each case, four controls were randomly selected from cohort members alive at age 3-months. Multivariable logistic regression was used to identify factors associated with these deaths.

Results

Overall, 112 adverse pregnancy outcomes (44 stillbirths, 19/1,000 births; 68 neonatal deaths, 29/1,000 live births) were reported. Of the stillbirths 25 (56.8%) were fresh. The main causes of neonatal death were birth asphyxia (35%), sepsis (28%) and preterm birth (19%). History of bleeding during pregnancy was the strongest risk factor for stillbirths (adjusted odds ratio 22.4 [95% confidence interval 2.5, 197.5]) and neonatal deaths (adjusted odds ratio 19.6 [95% confidence interval 2.1, 178.8]). Adequate maternal nutrition was associated with decreased risk of neonatal death (adjusted odds ratio 0.4 [95% confidence interval 0.2, 0.8]).

Conclusions

Identifying high-risk pregnancies during gestation and ensuring adequate antenatal and obstetric care needs to be a priority for any community-based maternal and child health program in similar settings.     

Mothers' birth weight and survival of their offspring: population based study.

OBJECTIVE: To test the hypothesis that a baby''s survival is related to the mother''s birth weight. DESIGN: Population based dataset for two generations. SETTING: Population registry in Norway. SUBJECTS: All birth records for women born in Norway since 1967 were linked to births during 1981-94, thereby forming 105104 mother-offspring units. MAIN OUTCOME MEASURES: Perinatal mortality specific for weight for offspring in groups of maternal birth weight (with 500 g categories in both). RESULTS: A mother''s birth weight was strongly associated with the weight of her baby. Maternal birth weight was associated with perinatal survival of her baby only for mothers with birth weights under 2000 g. These mothers were more likely to lose a baby in the perinatal period (odds ratio 2.3, 95% confidence interval 1.4 to 3.7). Among mothers with a birth weight over 2000 g there was no overall association between mother''s weight and infant survival. There was, however, a strong interaction between mother''s birth weight, infant birth weight, and infant survival. Mortality among small babies was much higher for those whose mothers had been large at birth. For example, babies weighing 2500-2999 g had a threefold higher mortality if their mother''s birth weight had been high (> or = 4000 g) than if the mother had been small (2500-2999 g). CONCLUSION: Mothers who weighed less than 2000 g at birth have a higher risk of losing their own babies. For mothers who weighed > or = 2000 g their birth weight provides a benchmark for judging the growth of their offspring. Babies who are small relative to their mother''s birth weight are at increased risk of mortality.