The influence of antenatal and maternal factors on stillbirths and neonatal deaths in New South Wales, Australia

This study identified the influences of maternal socio-demographic and antenatal factors on stillbirths and neonatal deaths in New South Wales, Australia. Bivariate and multivariate analyses were used to explore the association of selected antenatal and maternal characteristics with stillbirths and neonatal deaths. The findings of this study showed that stillbirths and neonatal deaths significantly varied by infant sex, maternal age, Aboriginality, maternal country of birth, socioeconomic status, parity, maternal smoking behaviour during pregnancy, maternal diabetes mellitus, maternal hypertension, antenatal care, plurality of birth, low birth weight, place of birth, delivery type, maternal deaths and small gestational age. First-born infants, twins and infants born to teenage mothers, Aboriginal mothers, those who smoked during the pregnancy and those of lower socioeconomic status were at increased risk of stillbirths and neonatal deaths. The most common causes of stillbirths were conditions originating in the perinatal period: intrauterine hypoxia and asphyxia. Congenital malformations, including deformities and chromosomal abnormalities, and disorders related to slow fetal growth, short gestation and low birth weight were the most common causes of neonatal deaths. The findings indicate that very low birth weight (less than 2,000 g) contributed 75.6% of the population-attributable risks to stillbirths and 59.4% to neonatal deaths. Low gestational age (less than 32 weeks) accounted for 77.7% of stillbirths and 87.9% of neonatal deaths. The findings of this study suggest that in order to reduce stillbirths and neonatal deaths, it is essential to include strategies to predict and prevent prematurity and low birth weight, and that there is a need to focus on anti-smoking campaigns during pregnancy, optimizing antenatal care and other healthcare programmes targeted at the socially disadvantaged populations identified in this study.     

Measures of performance in Scottish maternity hospitals.

OBJECTIVE--To develop measures of hospital performance over time with particular reference to maternal and neonatal care by controlling for case mix. DESIGN--Analysis of computerised records of births. SETTING--Scotland, 1980-7. SUBJECTS--Over half a million singleton live births and stillbirths. MAIN OUTCOME MEASURES--Numbers of perinatal deaths and caesarean sections. RESULTS--Scottish maternity hospitals perform more or less equally with regard to perinatal mortality. When caesarean sections are considered, there is evidence that hospitals differ in their treatment of different groups of women; in two examples one hospital had an increased rate among women of parity 2 or more and another had a reduced rate of repeat caesarean section. CONCLUSIONS--Developing measures of performance over time by controlling for case mix is a valid system for monitoring hospital outcomes and activity, and allows comparison either between hospitals or with data for all Scottish maternity hospitals. Hospital profiles permit identification of differences for particular patient groups after allowance is made for other case mix variables.     

Incidence of anencephaly in Jamaica

Information was collected on 2,197 stillbirths and neonatal deaths on the island of Jamaica during the 12 month period September 1986 to August 1987 as part of the population based nationwide Jamaican Perinatal Morbidity and Mortality Survey. There were 14 cases of anencephalus giving an incidence of 0.26 per 1,000 total births. One of these cases was associated with the amniotic band syndrome; excluding this, the incidence would be even lower (0.24 per 1,000). There was no apparent association with social class, maternal age, or parity. The rate found in Jamaica is considerably lower than found in any other national population study.     

The Effect of Changing Patterns of Obstetric Care in Scotland (1980–2004) on Rates of Preterm Birth and Its Neonatal Consequences: Perinatal Database Study

Background

Rates of preterm birth are rising worldwide. Studies from the United States and Latin America suggest that much of this rise relates to increased rates of medically indicated preterm birth. In contrast, European and Australian data suggest that increases in spontaneous preterm labour also play a role. We aimed, in a population-based database of 5 million people, to determine the temporal trends and obstetric antecedents of singleton preterm birth and its associated neonatal mortality and morbidity for the period 1980–2004.

Methods and Findings

There were 1.49 million births in Scotland over the study period, of which 5.8% were preterm. We found a percentage increase in crude rates of both spontaneous preterm birth per 1,000 singleton births (10.7%, p<0.01) and medically indicated preterm births (41.2%, p<0.01), which persisted when adjusted for maternal age at delivery. The greater proportion of spontaneous preterm births meant that the absolute increase in rates of preterm birth in each category were similar. Of specific maternal complications, essential and pregnancy-induced hypertension, pre-eclampsia, and placenta praevia played a decreasing role in preterm birth over the study period, with gestational and pre-existing diabetes playing an increasing role. There was a decline in stillbirth, neonatal, and extended perinatal mortality associated with preterm birth at all gestation over the study period but an increase in the rate of prolonged hospital stay for the neonate. Neonatal mortality improved in all subgroups, regardless of obstetric antecedent of preterm birth or gestational age. In the 28 wk and greater gestational groups we found a reduction in stillbirths and extended perinatal mortality for medically induced but not spontaneous preterm births (in the absence of maternal complications) although at the expense of a longer stay in neonatal intensive care. This improvement in stillbirth and neonatal mortality supports the decision making behind the 34% increase in elective/induced preterm birth in these women. Although improvements in neonatal outcomes overall are welcome, preterm birth still accounts for over 66% of singleton stillbirths, 65% of singleton neonatal deaths, and 67% of infants whose stay in the neonatal unit is “prolonged,” suggesting this condition remains a significant contributor to perinatal mortality and morbidity.

Conclusions

In our population, increases in spontaneous and medically induced preterm births have made equal contributions to the rising rate of preterm birth. Despite improvements in related perinatal mortality, preterm birth remains a major obstetric and neonatal problem, and its frequency is increasing. Please see later in the article for the Editors'' Summary     

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.     

Perinatal mortality: a continuing collaborative regional survey.

A collaborative survey of perinatal mortality in each district of the Northern region set up in July 1980 was able to obtain information on 99% of all the registered perinatal deaths among babies born in 1981-2 to mothers resident in the region. There were 12.4 perinatal deaths/1000 births over this two year period, but 41% of the stillbirths and early neonatal deaths were of babies with a lethal malformation or weighing less than 1000 g at birth (or both). All causes of perinatal mortality had become less common than they had been at the time of the National Birthday Trust survey in 1958, though there had been a relatively small decrease in the number of deaths due to malformation (in the absence of any neural tube defect) and in the number of stillbirths of normally developed fetuses: 36% of the antepartum stillbirths among non-malformed singleton fetuses were associated with poor fetal growth (weight below the fifth centile at birth) and 21% were due to sudden unexplained placental abruption.     

Maternal factors affecting reproduction in a breeding colony of cynomolgus macaques (Macaca fascicularis)

A breeding colony of cynomolgus macaques (Macaca fascicularis), composed of imported and colony-born animals and established for 9 years, was evaluated for maternal factors associated with reproductive failure. The factors evaluated included age, gravidity, parity, origin, previous stillbirths, clinical incidents and type of housing. The effects of each factor on pregnancy rate (PR), stillbirth rate (SR), infant mortality rate (IMR) and pregnancy success (PS) were evaluated. The overall colony rates were: PR = 53%, SR = 22%, IMR = 22%, and PS = 60%. Neonatal death rate for the group was 12%. Pregnancy rate was most affected by maternal factors. Clinical incidents occurring during pregnancy were associated with a significant increase in the stillbirth rate, but did not affect infant mortality rate. Maternal age did not affect any of the measures of reproductive output. Pregnancy rate peaked at 6-8 years of age and decreased thereafter, while pregnancy success peaked at 9-11 years of age. Gravidity and parity had a positive linear relationship with pregnancy rate.     

Social class as a risk factor for infant mortality in an Australian population

Studies in other countries have identified social class as a risk factor for infant mortality. In Australia there is no systematic collection of population data by social class, partly due to the absence of a recognized measure. The use of occupational prestige as an indicator of social class is discussed and Australian prestige scales reviewed. In a population based study, logistic regression analysis of infant mortality in an Australian (NSW) population shows the effects of social class on infant mortality which remain when maternal age, marital status and parity are controlled.     

Leatherwork: a possible hazard to reproduction.

A retrospective study was carried out aimed at eliciting the causes of perinatal death in Leicestershire between 1976 and 1982. Case notes were reviewed and the mothers interviewed in over 1000 cases. An analysis of maternal occupations showed that leatherworkers were at increased risk of having a perinatal death, particularly from congenital malformations and macerated stillbirths, even when compared with other manual workers in the same social class. The excess risk occurred in all towns of the county where leatherwork was undertaken. Further investigation is needed of the materials used in the leather industry in order to ensure that risks are minimised. Fecund women working in the industry should be informed of any residual risk if these findings are confirmed.     

Perinatal mortality by birth order within cohorts based on sibship size.

Cross-sectional surveys of perinatal mortality show a U-shaped curve when plotted against parity, implying that fourth and subsequent babies are at increased risk. Our study of a large, population-based longitudinal data set shows that this result is an artefact and that perinatal mortality falls with increasing parity. Within cohorts of mothers based on attained sibship size the perinatal mortality decreases with increasing parity and increases with sibship size. These associations, which are not noticeably affected by maternal age, ssem in part to operate through an association between parity, sibship size, and birth weight. This analysis shows the importance of using longitudinal data in analysing such relations.     

Sex differential patterns in perinatal deaths in Italy

In industrialized countries, male excess is generally found in early deaths, despite the overall decrease in mortality. We studied the association between sex and some factors generally considered crucial for babies' survival, such as mother's age and education, birth order, and gestational age, in order to gain insight into the causes underlying the persisting higher vulnerability of male sex in early life. The analysis was performed on babies dying during the perinatal period. These were subdivided into those who were stillborn and those who died during the first week of extrauterine life. A higher male excess among babies dying during the neonatal period than among those who were stillborn was always found in all classes of all factors. The finding of such generalized male overmortality in the early extrauterine period of life, together with the patterns shown by the temporal sex ratio in stillbirths and in early deaths, supports the hypothesis of a postponement of male risk from late fetal into neonatal life.     

Reproductive failure in macaques

Reproductive failure among captive and free-ranging macaques is common. Many females experience amenorrhea or anovular cycles. Females who successfully conceive often lose the conceptus before implantation. After implantation, fetuses are aborted because of maternal, paternal, fetal, or placental abnormalities. Death postpartum is likely if infants are premature or if animals are subject to social stress, especially trauma. Based on published reports, reproductive failure among macaques includes an average of 16.3% abortions, 9.9% stillbirths, 21.9% neonatal deaths, and 15.2% infant deaths.     

Perinatal mortality in eastern Uganda: a community based prospective cohort study

Background

To achieve a child mortality reduction according to millennium development goal 4, it is necessary to considerably reduce neonatal mortality. We report stillbirth and early neonatal mortality risks as well as determinants of perinatal mortality in Eastern Uganda.

Methods

A community-based prospective cohort study was conducted between 2006 and 2008. A total of 835 pregnant women were followed up for pregnancy outcome and survival of their children until 7 days after delivery. Mother''s residence, age, parity, bed net use and whether delivery took place at home were included in multivariable regression analyses to identify risk factors for perinatal death.

Results

The stillbirth risk was 19 per 1,000 pregnancies and the early neonatal death risk 22 per 1,000 live births. Overall, the perinatal mortality risk was 41 [95%CI: 27, 54] per 1,000 pregnancies. Of the deaths, 47% followed complicated deliveries and 24% preterm births. Perinatal mortality was 63/1,000 pregnancies among teenage mothers, 76/1,000 pregnancies among nulliparous women and 61/1,000 pregnancies among women delivering at home who, after controlling for potential confounders, had a 3.7 (95%CI: 1.8, 7.4) times higher perinatal mortality than women who gave birth in a health facility. This association was considerably stronger among nulliparous women [RR 8.0 (95%CI: 2.9, 21.6)] than among women with a previous live birth [RR 1.8 (95%CI: 0.7, 4.5)]. All perinatal deaths occurred among women who did not sleep under a mosquito net. Women living in urban slums had a higher risk of losing their babies than those in rural areas [RR: 2.7 (95%CI: 1.4, 5.3)].

Conclusion

Our findings strengthen arguments for ensuring that pregnant women have access to and use adequate delivery facilities and bed nets.     

Quality of obstetric care provided for Asian immigrants in Leicestershire.

Between 1976 and 1981 some 939 perinatal deaths occurred to women living in Leicestershire, of which 128 (14%) were to Asian women. The qualifications of the general practitioners, the gestation at which women start antenatal care, and perinatal death were used as structural, process, and outcome measures for evaluating the services provided to Asian immigrants within this population. Perinatal deaths were divided into four groups: congenital malformation, macerated stillbirth, asphyxia in labour, and immaturity. Asian mothers had one and a half times the risk of perinatal mortality when social class, parity, height, legitimacy, and the general practitioner''s qualifications were taken into account. Asian and non-Asian mothers with general practitioners who were not on the obstetric list had more than twice the risk of a perinatal death when a similar adjustment was made. Recommendations include priority allocation of community midwives to practitioners not on the obstetric list, the establishment of postgraduate courses for such doctors, and the continued evaluation of the effect of such proposals on perinatal mortality.     

The epidemiology of low birth weight; changes in incidence in Aberdeen, 1948-72

Changes in the incidence of low birth weight (defined as 2500 gm or less) in Aberdeen, Scotland are explored. The article also focuses on the perinatal mortality rate associated with unexplained low birth weight (LBW). Results, when analysed in terms of age, parity and social class of the mother, showed that in para 0 the incidence was highest in 1948-52. There was very little variation in incidence in each five year group in terms of para 1. The incidence of LBW was most strongly influenced by the socioeconomic climate at the time of the mother's birth. At least in Aberdeen the incidence of LBW in short women was twice that in tall women. The author concludes that the epidemiological characteristics of LBW is very closely associated with the changes in the socioeconomic conditions in Britain in the last decade which have affected health, nutrition and reproductive efficiency.     

Perinatal deaths: analysis by clinical cause to assess value of induction of labour.

Over the 10 years 1966-75 the rate of induction of labour in the Glasgow Royal Maternity Hospital has increased from 16-3% of all births. During the same period perinatal mortality fell from 33 to 22 per 1000, mainly because of significantly fewer deaths due to antepartum haemorrhage; trauma; maternal diseases; and unknown causes in mature babies. The reduction in the number of deaths of unknown causes in mature fetuses was achieved by preventing deaths occurring after 40 weeks and was recorded in all age and parity groups. The results suggested that increased use of induction of labour has contributed to the improved perinatal mortality rate.     

The baboon model (Papio hamadryas) of fetal loss: maternal weight,age, reproductive history and pregnancy outcome

Background Several risk factors are associated with the incidence of human stillbirths. The prevention of stillbirths in women is a pressing clinical problem. Methods We reviewed 402 pathology records of fetal loss occurring in a large baboon (Papio spp.) colony during a 15‐year period. Clinical histories of 565 female baboons with one or more fetal losses during a 20‐year period were analyzed for weight, age, and reproductive history. Results Fetal loss was most common at term (35.57%) and preterm (28.61%) and less common in the first half of gestation (11.20%) and post‐term (5.22%). Greater maternal weight, older age, history of stillbirth and higher parity were independent predictors for stillbirth. An exponential increase in the incidence of fetal loss was observed beginning at age 14 years in baboons. Conclusions Fetal loss and maternal risk factors associated with stillbirths in baboons were similar to those documented in women.     

Social class differences in infant mortality in Sweden: comparison with England and Wales.

OBJECTIVES--To investigate social class differences in infant mortality in Sweden in the mid-1980s and to compare their magnitude with that of those found in England and Wales. DESIGN--Analysis of risk of infant death by social class in aggregated routine data for the mid-1980s, which included the linkage of Swedish births to the 1985 census. SETTING--Sweden and England and Wales. SUBJECTS--All live births in Sweden (1985-6) and England and Wales (1983-5) and corresponding infant deaths were analysed. The Swedish data were coded to the British registrar general''s social class schema. MAIN OUTCOME MEASURES--Risk of death in the neonatal and postneonatal period. RESULTS--Taking the non-manual classes as the reference group, in the neonatal period in Sweden the manual social classes had a relative risk for mortality of 1.20 (95% confidence interval 1.02 to 1.43) and those not classified into a social class a relative risk of 1.08 (0.88 to 1.33). In the postneonatal period the equivalent relative risks were 1.38 (1.08 to 1.77) for manual classes and 2.14 (1.65 to 2.79) for the residual; these are similar to those for England and Wales (1.43 (1.36 to 1.51) for manual classes, 2.62 (2.45 to 2.81) for the residual). CONCLUSIONS--The existence of an equitable health care system and a strong social welfare policy in Sweden has not eliminated inequalities in post-neonatal mortality. Furthermore, the very low risk of infant death in the Swedish non-manual group (4.8/1000 live births) represents a target towards which public health interventions should aim. If this rate prevailed in England and Wales, 63% of postneonatal deaths would be avoided.     

Prepregnancy Obesity and Risks of Stillbirth

BackgroundWe examined the association of maternal obesity with risk of stillbirth, focusing on whether the pattern of results varied by gestational age or maternal race-ethnicity or parity.MethodsAnalyses included 4,012 stillbirths and 1,121,234 liveborn infants delivered in California from 2007–2010. We excluded stillbirths due to congenital anomalies, women with hypertensive disorders or diabetes, and plural births, to focus on fetuses and women without these known contributing conditions. We used Poisson regression to estimate relative risks (RR) and 95% confidence intervals (CI). Separate models were run for stillbirths delivered at 20–23, 24–27, 28–31, 32–36, 37–41 weeks, relative to liveborn deliveries at 37–41 weeks.ResultsFor stillbirth at 20–23 weeks, RRs were elevated for all race-ethnicity and parity groups. The RR for a 20-unit change in BMI (which reflects the approximate BMI difference between a normal weight and an Obese III woman) was 3.5 (95% CI 2.2, 5.6) for nulliparous white women and ranged from 1.8 to 5.0 for other sub-groups. At 24–27 weeks, the association was significant (p<0.05) only for multiparous non-Hispanic whites; at 28–31 weeks, for multiparous whites and nulliparous whites and blacks; at 32–36 weeks, for multiparous whites and nulliparous blacks; and at 37–41 weeks, for all groups except nulliparous blacks. The pattern of results was similar when restricted to stillbirths due to unknown causes and somewhat stronger when restricted to stillbirths attributable to obstetric causes.ConclusionIncreased risks were observed across all gestational ages, and some evidence of heterogeneity of the associations was observed by race-ethnicity and parity.     

The effect of divorce on infant mortality in a remote area of Bangladesh

The process of divorce is usually lengthy and hazardous, and can start quarrels that can lead to the abuse of women and their children. This study examines the effects of divorce on neonatal and postneonatal mortality of babies born before and after divorce in Teknaf, a remote area of Bangladesh. The longitudinal demographic surveillance system (DSS) followed 1,762 Muslim marriages in 1982-83 for 5 years to record divorce, deaths of spouse, emigration and births. It recorded 2,696 live births during the follow-up period, and their survival status during infancy. Logistic regression models were used to estimate the effect of divorce on neonatal and postneonatal mortality, controlling for maternal age at birth, parity, sex of the child and household economic status. The odds of neonatal and postneonatal deaths among babies born after divorce or less than 12 months before mothers were divorced were more than double the odds of those born to mothers of intact marriages. The odds of postneonatal deaths were two times higher among babies born more than 12 months before divorce happens than their peers. The high mortality of infants born before and after mothers were divorced may reflect how abusive marriage and divorce increase the vulnerability of women and children in rural Bangladesh. Divorce and abuse of women are difficult and intractable social and health problems that must be addressed.