Birth outcomes for teenage women in New South Wales, 1998-2003

Lifestyle and sociodemographic risk factors for stillbirth by region of residence in South Australia: a retrospective cohort study

BACKGROUND

Stillbirth rates remain a global priority and in Australia, progress has been slow. Risk factors of stillbirth are unique in Australia due to large areas of remoteness, and limited resource availability affecting the ability to identify areas of need and prevalence of factors associated with stillbirth. This retrospective cohort study describes lifestyle and sociodemographic factors associated with stillbirth in South Australia (SA), between 1998 and 2016.

METHODS

All restigered births in SA between 1998 ad 2016 are included. The primary outcome was stillbirth (birth with no signs of life ≥ 20 weeks gestation or ≥ 400 g if gestational age was not reported). Associations between stillbirth and lifestyle and sociodemographic factors were evaluated using multivariable logistic regression and described using adjusted odds ratios (aORs).

RESULTS

A total of 363,959 births (including 1767 stillbirths) were included. Inadequate antenatal care access (assessed against the Australian Pregnancy Care Guidelines) was associated with the highest odds of stillbirth (aOR 3.93, 95% confidence interval (CI) 3.41-4.52). Other factors with important associations with stillbirth were plant/machine operation (aOR, 1.99; 95% CI, 1.16-2.45), birthing person age ≥ 40 years (aOR, 1.92; 95% CI, 1.50-2.45), partner reported as a pensioner (aOR, 1.83; 95% CI, 1.12-2.99), Asian country of birth (aOR, 1.58; 95% CI, 1.19-2.10) and Aboriginal/Torres Strait Islander status (aOR, 1.50; 95% CI, 1.20-1.88). The odds of stillbirth were increased in regional/remote areas in association with inadequate antenatal care (aOR, 4.64; 95% CI, 2.98-7.23), birthing age 35-40 years (aOR, 1.92; 95% CI, 1.02-3.64), Aboriginal and/or Torres Strait Islander status (aOR, 1.90; 95% CI, 1.12-3.21), paternal occupations: tradesperson (aOR, 1.69; 95% CI, 1.17-6.16) and unemployment (aOR, 4.06; 95% CI, 1.41-11.73).

CONCLUSION

Factors identified as independently associated with stillbirth odds include factors that could be addressed through timely access to adequate antenatal care and are likely relevant throughout Australia. The identified factors should be the target of stillbirth prevention strategies/efforts. SThe stillbirth rate in Australia is a national concern. Reducing preventable stillbirths remains a global priority.

Maternal residential area effects on preterm birth, low birth weight and caesarean section in Australia: A systematic review

INTRODUCTION

In Australia, area of residence is an important health policy focus and has been suggested as a key risk factor for preterm birth (PTB), low birth weight (LBW) and cesarian section (CS) due to its influence on socioeconomic status, access to health services, and its relationship with medical conditions. However, there is inconsistent evidence about the relationship of maternal residential areas (rural and urban areas) with PTB, LBW, and CS. Synthesising the evidence on the issue will help to identify the relationships and mechanisms for underlying inequality and potential interventions to reduce such inequalities in pregnancy outcomes (PTB, LBW and CS) in rural and remote areas.

METHODS

Electronic databases, including MEDLINE, Embase, CINAHL, and Maternity & Infant Care, were systematically searched for peer-reviewed studies which were conducted in Australia and compared PTB, LBW or CS by maternal area of residence. Articles were appraised for quality using JBI critical appraisal tools.

RESULTS

Ten articles met the eligibility criteria. Women who lived in rural and remote areas had higher rates of PTB and LBW and lower rate of CS compared to their urban and city counterparts. Two articles fulfilled JBI's critical appraisal checklist for observational studies. Compared to women living in urban and city areas, women living in rural and remote areas were also more likely to give birth at a younger age (<20 years) and have chronic diseases such as hypertension and diabetes. They were also less likely to have higher levels of completing university degree education, private health insurance and births in private hospitals.

CONCLUSIONS

Addressing the high rate of pre-existing and/or gestational hypertension and diabetes, limited access of health services and a shortage of experienced health staff in remote and rural areas are keys to early identification and intervention of risk factors of PTB, LBW, and CS.

Social Determinants of Health and Adverse Outcomes in Adolescent Pregnancies

The association between adolescent childbearing and adverse maternal and birth outcomes has been well documented. Adverse adolescent pregnancy outcomes are associated with substantial risk of long-term morbidities for the young mother and their newborns. Multiple levels of social disadvantage have been related to adverse pregnancy outcomes among adolescent mothers. Patterns of cumulative social adversity define the most marginalized group of adolescents at the highest risk of experiencing adverse maternal and birth outcomes. Using a social determinants of health (SDOH) framework, we present an overview of the current scientific evidence on the influence of these conditions on adolescent pregnancy outcomes. Multiple SDOH such as residence in remote areas, low educational attainment, low socioeconomic status, and lack of family and community support have been linked with increased risk of adverse pregnancy outcomes among adolescents. Based on the PROGRESS-Plus equity framework, this review highlights some SDOH aspects that perinatal health researchers, clinicians, and policy makers should consider in the context of adolescent pregnancies. There is a need to acknowledge the intersectional nature of multiple SDOH when formulating clinical and societal interventions to address the needs of the most marginalized adolescent in this critical period of life.

Maternal Area of Residence, Socioeconomic Status, and Risk of Adverse Maternal and Birth Outcomes in Adolescent Mothers

OBJECTIVE

Adolescent pregnancy is a significant public health issue in Canada. Current evidence highlights the individual role of social determinants of health such as maternal residence and socioeconomic status (SES) on teen pregnancy outcomes. This study evaluated the joint association between residence/SES and adverse adolescent pregnancy outcomes.

METHODS

This was a population-based retrospective cohort study of all singleton, live deliveries (2010-2015) from women aged 15 to 19 who were registered in the Alberta Perinatal Health Program. Information on maternal residence and SES was extracted from the Pampalon Material Deprivation Index data set. The study categorized mothers into four risk dyads: rural/high SES, rural/low SES, urban/high SES, and urban/low SES. Adjusted odds ratios (ORs) of adverse pregnancy outcomes were calculated in logistic regression models (Canadian Task Force Classification II-2).

RESULTS

A total of 9606 births from adolescent mothers were evaluated. Thirty percent of adolescent mothers were classified as urban/high SES; 27% were urban/low SES; 7% were rural/high SES; and 36% were placed in the rural/low SES category. Compared with urban/high SES mothers, rural/low SES mothers had increased odds of postpartum hemorrhage (OR 1.57; 95% confidence interval [CI] 1.41-1.74), operative vaginal delivery (OR 1.37; 95% CI 1.18-1.60), Caesarean section (OR 1.39; 95% CI 1.19-1.62), large for gestational age infants (OR 1.39; 95% CI 1.16-1.66), low birth weight (OR 1.11; 95% CI 1.07-1.65), and preterm birth (OR 1.48; 95% CI 1.17-1.87).

CONCLUSION

Rural pregnant adolescents of low SES have the highest odds for adverse pregnancy outcomes. Social determinants of health that affect adolescent pregnancies need further examination to identify high-risk subgroups and understand pathways to health disparities in this vulnerable population.

Social determinants of health and adverse maternal and birth outcomes in adolescent pregnancies: A systematic review and meta-analysis

BACKGROUND

Adverse outcomes in adolescent pregnancies have been attributed to both biological immaturity and social determinants of health (SDOH). The present systematic review evaluated the evidence on the association between SDOH and adverse maternal and birth outcomes in adolescent mothers.

METHODS

Comprehensive literature searches were conducted to identify observational studies evaluating the relationship between SDOH and adverse adolescent pregnancy outcomes. Study selection, risk of bias appraisal, and data extraction of study characteristics were independently performed by two reviewers. Pooled odds ratios (pOR) with 95% confidence intervals (95% CI) were calculated to assess the association between SDOH and adverse birth outcomes.

RESULTS

Thirty-one studies met the inclusion criteria. The most frequently evaluated SDOH was race while the most commonly reported maternal and birth outcomes were caesarean section and preterm birth (PTB), respectively. The risk of bias of included studies was fair on the Newcastle-Ottawa Scale. Meta-analyses of retrospective cohort studies showed that, compared to White adolescent mothers, African American teens had increased odds of PTB (pOR 1.67; 95% CI 1.59, 1.75) and low birthweight (pOR 1.53; 95% CI 1.45, 1.62). Rural residence was consistently linked with PTB while low maternal socio-economic (SES) and illiteracy were found to increase the risk of adolescent maternal mortality and LBW infants.

CONCLUSION

Social determinants of health contribute to the risk of adverse pregnancy outcomes in adolescent mothers. African American race, rural residence, inadequate education, and low SES are markers for poor pregnancy outcomes in adolescent mothers. Further research needs to be done to understand the underlying causal pathways to inequalities in adolescent pregnancy outcomes.

Availability of Reproductive Health Care Services at Schools and Subsequent Birth Outcomes Among Adolescent Mothers

BACKGROUND

Adverse birth outcomes are more common among adolescent versus adult mothers, but little is known about school-based services that may improve birth outcomes in this group.

METHODS

Data from Waves I and IV of the National Longitudinal Study of Adolescent Health were analyzed. Girls and women who gave birth to singleton live infants after Wave I and before age 20, were still in secondary school while pregnant, and had complete data (N = 402) were included. Mothers reported infants' birthweight and gestational age. School administrators reported whether family planning counseling, diagnostic screening (including sexually transmitted diseases [STDs]), STD treatment, and prenatal/postpartum health care were provided on-site at school at Wave I. Multilevel models adjusted for individual and school characteristics were conducted.

RESULTS

Few schools offered reproductive health care services on-site. In multilevel analyses, availability of family planning counseling (Est. β = 0.21, 95% confidence interval [CI] 0.04-0.38 p < 0.05) and prenatal/postpartum health care (Est. β = 0.21, 95% CI 0.02-0.40 p < 0.05) were significantly associated with increased infant birthweight. No services examined were significantly associated with increased gestational age.

CONCLUSIONS

Some school-based reproductive health services may improve subsequent birth outcomes among adolescent mothers. Future analyses should examine the mechanisms by which services impact birth outcomes.

Risk factors of stillbirths in Victoria (Australia): A case-control study

Stillbirth is one of the most adverse pregnancy outcomes. The rate of stillbirth in high income countries has remained stagnant in recent decades. This study aimed to determine the incidence and risk factors of stillbirths specific to hospital-based deliveries in a secondary level hospital in Melbourne, Australia, over a 5-year period. We conducted a case-control study from January 2007 to December 2011. Univariate and multivariate analyses were conducted in STATA 12.1. The 5-year cumulative incidence of still-birth was 5.3 per 1000 total births (95% CI 4.3, 6.5). Univariate analysis revealed that higher body-mass index, smoking during pregnancy, haemoglobin level (≥14.5 g/dl), previous stillbirth, primiparity, marital status, previous caesarean section and reduced foetal movement in the 2 weeks prior to delivery were associated with increased risk of stillbirth. However, after adjustment for confounders in a multiple-regression model, only previous caesarean section (p = 0.006), unmarried (p = 0.004), high haemoglobin level (p = 0.007) and reduced foetal movement in the 2 weeks prior to delivery (p < 0.001) remained significantly associated with increased risk of stillbirth. The characteristics of our study population was similar to the population of state-wide survey in 2009, however, the incidence in our study was slightly lower. We concluded that previous caesarean section, pregnancy while being unmarried, higher haemoglobin level and reduced foetal movement in the 2 weeks before delivery were significant predictors of stillbirth. The identified risk factors were similar to other studies and the obstetric practice at the hospital or the demographics of the study population did not add to additional risk.

Maternal smoking and the risk of still birth: systematic review and meta-analysis

Background

Smoking in pregnancy is known to be associated with a range of adverse pregnancy outcomes, yet there is a high prevalence of smoking among pregnant women in many countries, and it remains a major public health concern. We have conducted a systematic review and meta-analysis to provide contemporary estimates of the association between maternal smoking in pregnancy and the risk of stillbirth.

Methods

We searched four databases namely MEDLINE, EMBASE, Psych Info and Web of Science for all relevant original studies published until 31^st December 2012. We included observational studies that measured the association between maternal smoking during pregnancy and the risk of stillbirth.

Results

1766 studies were screened for title analysis, of which 34 papers (21 cohorts, 8 case controls and 5 cross sectional studies) met the inclusion criteria. In meta-analysis smoking during pregnancy was significantly associated with a 47% increase in the odds of stillbirth (OR 1.47, 95% CI 1.37, 1.57, p < 0.0001). In subgroup analysis, smoking 1-9 cig/day and ≥10 cig/day was associated with an 9% and 52% increase in the odds of stillbirth respectively. Subsequently, studies defining stillbirth at ≥ 20 weeks demonstrated a 43% increase in odds for smoking mothers compared to mothers who do not smoke, (OR 1.43, 95% CI 1.32, 1.54, p < 0.0001), whereas studies with stillbirth defined at ≥ 24 weeks and ≥ 28 weeks showed 58% and 33% increase in the odds of stillbirth respectively.

Conclusion

Our review confirms a dose-response effect of maternal smoking in pregnancy on risk of stillbirth. To minimise the risk of stillbirth, reducing current smoking prevalence in pregnancy should continue to be a key public health high priority.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1552-5) contains supplementary material, which is available to authorized users.

Parent-child relationships, parental attitudes towards sex, and birth outcomes among adolescents

STUDY OBJECTIVE

To examine how parent-child relationships, parental control, and parental attitudes towards sex were related to pregnancy outcomes among adolescent mothers.

DESIGN

Prospective cohort study. Parental report of relationship satisfaction, disapproval of adolescent having sex, discussion around sexual health, and sexual communication attitudes, and adolescent report of relationship satisfaction, parental control, and parental disapproval of sex were examined as predictors of self-reported birth outcomes. Weighted multivariable linear regression models were run incorporating interactions by race.

SETTING

United States.

PARTICIPANTS

632 females who participated in Waves I and IV of the National Longitudinal Study of Adolescent Health (Add Health), a nationally-representative sample of students enrolled in grades 7-12 in 1994-95 and followed up in 2007-2008.

MAIN OUTCOME MEASURES

Birthweight and gestational age.

RESULTS

For Black adolescents, better parent-child relationship was associated with higher birthweight (0.14 kg, P < .05) and gestational age (0.75 weeks, P < .01), while higher parental disapproval of having sex (adjusted beta 0.15 kg, P < .05) were associated with higher birthweight. For non-Black adolescents, a moderate amount of discussion of birth control was associated with higher birthweight (0.19 kg, P < .01 and lower child-perceived parental disapproval of having sex was associated with higher birthweight (0.08 kg, P < .05) and gestational age (0.37 weeks, P < .05). Higher parental control was associated with a reduced likelihood of smoking during pregnancy and a greater likelihood of early prenatal care.

CONCLUSION

Parent-child relationships and attitudes about sex affect outcomes of pregnant adolescents.

Pre-Pregnancy Dating Violence and Birth Outcomes Among Adolescent Mothers in a National Sample

Although infants born to adolescent mothers are at increased risk of adverse birth outcomes, little is known about contributors to birth outcomes in this group. Given past research linking partner abuse to adverse birth outcomes among adult mothers, we explored associations between pre-pregnancy verbal and physical dating violence and the birth weight and gestational age of infants born to adolescent mothers. Data from the National Longitudinal Study of Adolescent Health Waves I (1995/1996), II (1996), and IV (2007/2008) were analyzed. Girls whose first singleton live births occurred after Wave II interview and before age 20 (N = 558) self-reported infants' birth weight and gestational age at Wave IV. Dating violence victimization (verbal and physical) in the 18 months prior to Wave II interview was self-reported. Controls included Wave I age, parent education, age at pregnancy, time between reporting abuse and birth, and childhood physical and sexual abuse. Weighted multivariable regression models were performed separately by race (Black/non-Black).On average, births occurred 2 years after Wave II interview. Almost one in four mothers reported verbal dating violence victimization (23.6%), and 10.1% reported physical victimization. Birth weight and prevalence of verbal dating violence victimization were significantly lower in Black compared with non-Black teen mothers. In multivariable analyses, negative associations between physical dating abuse and birth outcomes became stronger as time increased for Black mothers. For example, pre-pregnancy physical dating abuse was associated with 0.79 kilograms lower birth weight (p< .001) and 4.72 fewer weeks gestational age (p< .01) for Black mothers who gave birth 2 years post-reporting abuse. Physical dating abuse was unassociated with birth outcomes among non-Black mothers, and verbal abuse was unassociated with birth outcomes for all mothers. Reducing physical dating violence in adolescent relationships prior to pregnancy may improve Black adolescent mothers' birth outcomes. Intervening on long-term violence may be particularly important.

Neighborhood disadvantage, racial concentration and the birthweight of infants born to adolescent mothers

To study the relationship between neighborhood demographic characteristics (disadvantage, racial concentration) and the birthweight of infants born to adolescent mothers, potentially as mediated by smoking, prenatal care use, or perceptions of neighborhood safety. Data from Waves I and IV of the National Longitudinal Survey of Adolescent Health were analyzed. Birthweight (continuous) and low birthweight (<2.5 kg) of singleton infants born to non-Hispanic Black and non-Hispanic White adolescent mothers (<20 years) after Wave I were examined as outcomes. Neighborhood demographic characteristics included Census Block Group socioeconomic disadvantage and Black racial concentration. Possible mediators (smoking during pregnancy, early initiation of prenatal care, and perceptions of safety) were also examined. Controls for adolescent baseline age, age at pregnancy, body mass index (BMI) and parental education were included. Analyses were run stratified on race. Baseline continuous birthweight, BMI and neighborhood demographics varied significantly between non-Hispanic Black and White adolescent mothers, with Black adolescent mothers evidencing lower birthweight and higher BMI, neighborhood disadvantage and Black racial concentration. In multivariable analyses among Black adolescent mothers, Black racial concentration was positively associated with birthweight, and negatively associated with low birthweight; no mediators were supported. Neighborhood disadvantage and Black racial concentration were unassociated with birthweight outcomes among White adolescent mothers. Infants born to Black adolescent mothers evidenced higher birthweight with increasing Black neighborhood concentration. Further exploration of mechanisms by which Black racial concentration may positively impact birthweight is warranted.

Assessing spatial accessibility to maternity units in Shenzhen, China

BACKGROUND

With the rapid development of urbanization, pregnant population is growing rapidly in Shenzhen, and it has been a difficulty to serve more and more pregnant women and reduce spatial access disparities to maternity units (MUs). Understanding of the current status of accessibility to MUs is valuable for supporting the rational allocation of MUs in the future.

METHODS

Based on pregnant population data and MUs data, this study uses a two-step floating catchment area (2SFCA) method based on Geographic Information System (GIS) to analyze the current spatial accessibility to MUs, and then make a comparison between that to public MUs and private MUs.

RESULTS

Our analysis of the accessibility to all MUs within a distance of 20 km shows that the accessibilities of the areas alongside the traditional border management line are acceptable, meanwhile highlights some critical areas, such as the west part of Nanshan district and the vast east part of Longgang district. The comparison between spatial accessibility to public MUs and private MUs shows statistically significant difference.

DISCUSSION

Results of this study suggest a great effort should be made to improve the equity of spatial accessibility to MUs in Shenzhen. For policy-making, strategy for the siting and allocation of future MUs, no matter public or private, should guarantee the greatest spatial accessibility for every pregnant woman.

Predictors of birth weight and gestational age among adolescents

Although pregnant adolescents are at high risk of poor birth outcomes, the majority of adolescents go on to have full-term, healthy babies. Data from the National Longitudinal Study of Adolescent Health, a longitudinal study of a nationally representative sample of adolescents in grades 7-12 in the United States who were surveyed from 1994-1995 through 2008, were used to examine the epidemiology of preterm birth and low birth weight within this population. Outcomes of pregnancies were reported by participants in the fourth wave of data collection (when participants were 24-32 years of age); data were compared between female participants who reported a first singleton livebirth at less than 20 years of age (n = 1,101) and those who were 20 years of age or older (n = 2,846). Multivariable modeling was used to model outcomes; predictors included demographic characteristics and maternal health and behavior. Among black adolescents, low parental educational levels and older age at pregnancy were associated with higher birth weight, whereas low parental educational levels and being on birth control when one got pregnant were associated with higher gestational age. In nonblack adolescents, lower body mass index was associated with lower birth weight, whereas being unmarried was associated with lower gestational age. Predictors of birth outcomes may differ by age group and social context.

Predictors of healthy birth outcome in adolescents: a positive deviance approach

STUDY OBJECTIVE

Pregnant adolescents experience elevated rates of adverse birth outcomes compared to older mothers. Positive deviance inquiry is the identification of uncommon behaviors and traits that result in better health outcomes for individuals in a population that shares similar risks. The purpose of our study was to utilize a positive deviance framework to identify sociodemographic and behavioral characteristics associated with a healthy birth outcome among adolescents.

DESIGN

This is a retrospective cohort study design.

SETTING

We performed a secondary data analysis of vital records data from the State of Louisiana between January 1, 1995 and December 31, 2007.

PARTICIPANTS

Data included birth certificates from 35,013 Louisiana mothers age ≤19.

MAIN OUTCOME MEASURE

A healthy birth was defined as having an infant of weight between 2500 g and 4000 g, delivered vaginally without induction or instrumented delivery and in the absence of pregnancy, obstetric, or neonatal complications and anomalies.

RESULTS

Twenty-one percent of the study population was classified as positive deviants with healthy births. Multivariate log-linear regression was used to model predictors of healthy birth. Adolescents who were older, non-black, multiparous, non-smoking, married, gained a medium amount of weight, had a longer inter-pregnancy interval or received adequate prenatal care were most likely to experience a healthy pregnancy and birth. Ethnicity, alcohol use, father's information on the birth certificate and paternal characteristics did not significantly predict a positive birth outcome.

CONCLUSION

Characterizing positive deviant adolescents may help identify special populations for targeted intervention and important modifiable behaviors for the promotion of better birth outcomes in all young mothers.

The impact of early age at first childbirth on maternal and infant health

The objective of this review was to assess whether early age at first childbirth is associated with increased risk of poor pregnancy outcomes. Early age at childbirth is variously defined in studies of its effect on maternal and infant health. In this systematic review, we limit analysis to studies of at least moderate quality that examine first births among young mothers, where young maternal age is defined as low gynaecological age (≤ 2 years since menarche) or as a chronological age ≤ 16 years at conception or delivery. We conduct meta-analyses for specific maternal or infant health outcomes when there are at least three moderate quality studies that define the exposure and outcome in a similar manner and provide odds ratios or risk ratios as their effect estimates. We conclude that the overall evidence of effect for very young maternal age (<15 years or <2 years post-menarche) on infant outcomes is moderate; that is, future studies are likely to refine the estimate of effect or precision but not to change the conclusion. Evidence points to an impact of young maternal age on low birthweight and preterm birth, which may mediate other infant outcomes such as neonatal mortality. The evidence that young maternal age increases risk for maternal anaemia is also fairly strong, although information on other nutritional outcomes and maternal morbidity/mortality is less clear. Many of the differences observed among older teenagers with respect to infant outcomes may be because of socio-economic or behavioural differences, although these may vary by country/setting. Future, high quality observational studies in low income settings are recommended in order to address the question of generalisability of evidence. In particular, studies in low income countries need to consider low gynaecological age, rather than simply chronological age, as an exposure. As well, country-specific studies should measure the minimum age at which childbearing for teens has similar associations with health as childbearing for adults. This 'tipping point' may vary by the underlying physical and nutritional health of girls and young women.

Young mothers' lived experiences prior to becoming pregnant in rural Victoria: a phenomenological study

OBJECTIVE

To explore the lived experiences and social context prior to becoming pregnant, of women who became mothers during adolescence in rural Victoria.

DESIGN

Qualitative interpretive phenomenological study using semistructured interviews.

SETTING

Rural community in North East Victoria, Australia.

PARTICIPANTS

Four rural women who gave birth to a child between the ages of 15 and 19.

RESULTS

Five themes emerged from the data as being essential to the participants' experiences prior to pregnancy. These included feeling isolated; life change: transition into adulthood; support and understanding in sexual relationships; feeling dissatisfied; and overcoming adversity. Participants' provided practical recommendations to improve life for young people in rural areas through reflecting on their own experiences.

CONCLUSION

These findings highlight the complex nature of rural young women's experiences leading up to pregnancy and suggest that early motherhood might be largely reflective of the social environment in which one lives prior to pregnancy. Providing somewhere safe to go, organised and appropriate social activities and increasing access to health services were identified as being pertinent to improving experiences for rural young people prior to pregnancy. Health professionals should consider the importance of supporting young women through non-judgemental, approachable and accessible services.

Stillbirths: the way forward in high-income countries

Stillbirth rates in high-income countries declined dramatically from about 1940, but this decline has slowed or stalled over recent times. The present variation in stillbirth rates across and within high-income countries indicates that further reduction in stillbirth is possible. Large disparities (linked to disadvantage such as poverty) in stillbirth rates need to be addressed by providing more educational opportunities and improving living conditions for women. Placental pathologies and infection associated with preterm birth are linked to a substantial proportion of stillbirths. The proportion of unexplained stillbirths associated with under investigation continues to impede efforts in stillbirth prevention. Overweight, obesity, and smoking are important modifiable risk factors for stillbirth, and advanced maternal age is also an increasingly prevalent risk factor. Intensified efforts are needed to ameliorate the effects of these factors on stillbirth rates. Culturally appropriate preconception care and quality antenatal care that is accessible to all women has the potential to reduce stillbirth rates in high-income countries. Implementation of national perinatal mortality audit programmes aimed at improving the quality of care could substantially reduce stillbirths. Better data on numbers and causes of stillbirth are needed, and international consensus on definition and classification related to stillbirth is a priority. All parents should be offered a thorough investigation including a high-quality autopsy and placental histopathology. Parent organisations are powerful change agents and could have an important role in raising awareness to prevent stillbirth. Future research must focus on screening and interventions to reduce antepartum stillbirth as a result of placental dysfunction. Identification of ways to reduce maternal overweight and obesity is a high priority for high-income countries.

Major risk factors for stillbirth in high-income countries: a systematic review and meta-analysis

BACKGROUND

Stillbirth rates in high-income countries have shown little or no improvement over the past two decades. Prevention strategies that target risk factors could be important in rate reduction. This systematic review and meta-analysis was done to identify priority areas for stillbirth prevention relevant to those countries.

METHODS

Population-based studies addressing risk factors for stillbirth were identified through database searches. The factors most frequently reported were identified and selected according to whether they could potentially be reduced through lifestyle or medical intervention. The numbers attributable to modifiable risk factors were calculated from data relating to the five high-income countries with the highest numbers of stillbirths and where all the data required for analysis were available. Odds ratios were calculated for selected risk factors, from which population-attributable risk (PAR) values were calculated.

FINDINGS

Of 6963 studies initially identified, 96 population-based studies were included. Maternal overweight and obesity (body-mass index >25 kg/m(2)) was the highest ranking modifiable risk factor, with PARs of 8-18% across the five countries and contributing to around 8000 stillbirths (≥22 weeks' gestation) annually across all high-income countries. Advanced maternal age (>35 years) and maternal smoking yielded PARs of 7-11% and 4-7%, respectively, and each year contribute to more than 4200 and 2800 stillbirths, respectively, across all high-income countries. In disadvantaged populations maternal smoking could contribute to 20% of stillbirths. Primiparity contributes to around 15% of stillbirths. Of the pregnancy disorders, small size for gestational age and abruption are the highest PARs (23% and 15%, respectively), which highlights the notable role of placental pathology in stillbirth. Pre-existing diabetes and hypertension remain important contributors to stillbirth in such countries.

INTERPRETATION

The raising of awareness and implementation of effective interventions for modifiable risk factors, such as overweight, obesity, maternal age, and smoking, are priorities for stillbirth prevention in high-income countries.

FUNDING

The Stillbirth Foundation Australia, the Department of Health and Ageing, Canberra, Australia, and the Mater Foundation, Brisbane, Australia.

What causes racial disparities in very preterm birth? A biosocial perspective

Very preterm birth (<32 weeks' gestation) occurs in approximately 2% of livebirths but is a leading cause of infant mortality and morbidity in the United States. African-American women have a 2-fold to 3-fold elevated risk compared with non-Hispanic white women for reasons that are incompletely understood. This paper reviews the evidence for the biologic and social patterning of very preterm birth, with attention to leading hypotheses regarding the etiology of the racial disparity. A systematic review of the literature in the MEDLINE, CINAHL, PsycInfo, and EMBASE indices was conducted. The literature to date suggests a complex, multifactorial causal framework for understanding racial disparities in very preterm birth, with maternal inflammatory, vascular, or neuroendocrine dysfunction as proximal pathways and maternal exposure to stress, racial differences in preconceptional health, and genetic, epigenetic, and gene-environment interactions as more distal mediators. Interpersonal and institutionalized racism are mechanisms that may drive racially patterned differences. Current literature is limited in that research on social determinants and biologic processes of prematurity has been generally disconnected. Improved etiologic understanding and the potential for effective intervention may come with better integration of these research approaches.

Is segregation bad for your health?

For decades, racial residential segregation has been observed to vary with health outcomes for African Americans, although only recently has interest increased in the public health literature. Utilizing a systematic review of the health and social science literature, the authors consider the segregation-health association through the lens of 4 questions of interest to epidemiologists: How is segregation best measured? Is the segregation-health association socially or biologically plausible? What evidence is there of segregation-health associations? Is segregation a modifiable risk factor? Thirty-nine identified studies test an association between segregation and health outcomes. The health effects of segregation are relatively consistent, but complex. Isolation segregation is associated with poor pregnancy outcomes and increased mortality for blacks, but several studies report health-protective effects of living in clustered black neighborhoods net of social and economic isolation. The majority of reviewed studies are cross-sectional and use coarse measures of segregation. Future work should extend recent developments in measuring and conceptualizing segregation in a multilevel framework, build upon the findings and challenges in the neighborhood-effects literature, and utilize longitudinal data sources to illuminate opportunities for public health action to reduce racial disparities in disease.

Degree of rural isolation and birth outcomes

Little is known about how birth outcomes vary in rural areas by degree of rural isolation. We conducted a retrospective cohort study of all births in Quebec, 1991-2000 to assess birth outcomes by the degree of rural isolation according to metropolitan influence as measured by work force commuting flows between rural and urban areas. Compared with urban areas, crude risks of preterm birth, small-for-gestational age birth, stillbirth, neonatal death and postneonatal death were similar in rural areas with strong metropolitan influence, but were significantly higher for preterm birth, stillbirth and postneonatal death in rural areas with weak or no metropolitan influence, and for neonatal death in rural areas with no metropolitan influence. Adjustment for maternal characteristics (age, mother tongue, education, marital status, parity, plurality and infant sex) attenuated the associations. The adjusted odds ratios [95% confidence intervals] were 1.36 [1.12, 1.64] for stillbirth in rural areas with weak metropolitan influence, 1.63 [1.14, 2.32] for neonatal death in rural areas with no metropolitan influence, 1.78 [1.21, 2.63] and 1.37 [1.07, 1.75] for postneonatal death in rural areas with weak and no metropolitan influence, respectively. Much higher neonatal death rates were observed for preterm or low-birthweight babies in rural areas with no metropolitan influence, suggesting inadequate access to optimal neonatal care. We conclude that birth outcomes in rural areas differ according to the degree of rural isolation. Fetuses and infants of mothers from rural areas with weak or no metropolitan influence are particularly vulnerable to the risks of death during the perinatal and postnatal periods.

Adverse perinatal outcomes of adolescent pregnancies in Cameroon

BACKGROUND

There are geographic variations in fetal outcomes of adolescent pregnancies because of socio-economic differences between regions and countries. The aim of our study was to determine adverse fetal outcomes associated with adolescent pregnancies in Cameroon.

METHODS

A cross-sectional study to compare the outcomes of 268 singleton, adolescent pregnancies with 832 controls, delivered in four referral hospitals in Yaounde (Cameroon), between November 2004 and April 2005.

RESULTS

The adverse fetal outcomes related to adolescent pregnancies were low birth weight (<2,500 g) (odds ratios [OR], 1.71; confidence interval [CI], 1.15-2.50), premature babies (<37 weeks) (OR, 1.77; CI, 1.24-2.52) and early neonatal death (OR, 2.18; CI, 1.04-4.48). The rates of stillbirth and intrauterine growth retardation were not significantly higher among adolescents. Adverse maternal outcome associated with adolescent pregnancies were eclampsia (OR, 3.18; CI, 1.21-8.32), preeclampsia (OR, 1.99; CI, 1.24-3.15), perineal tear (OR, 1.45; CI, 1.06-1.99) and episiotomy (OR, 1.82; CI, 1.20-2.73). Caesarean delivery, instrumental delivery and premature rupture of membranes were not significantly associated with adolescent pregnancy. Maternal factors associated with adverse fetal outcome in adolescents were maternal age, number of prenatal visits <4, and the state of being unemployed.

CONCLUSION

Adolescent pregnancies are associated with both adverse fetal and maternal outcomes in Cameroon. Improving compliance with prenatal care could significantly reduce the frequency of adverse fetal outcomes in adolescent populations in Cameroon.