Risk factors for low birth weight in a socio-economically disadvantaged population: parity, marital status, ethnicity and cigarette smoking

A cohort study of dysmenorrhea and risk of low birth weight

OBJECTIVE

Little is known about the association between maternal history of dysmenorrhea and perinatal outcomes. The aim of this study was to investigate the association between maternal history of dysmenorrhea and low birth weight (LBW).

METHODS

A total of 6754 pregnant women were recruited from the ongoing prospective cohort study in Guangxi, China, in 2015-2018. Information on the maternal history of dysmenorrhea was obtained by questionnaires including visual analog scale (VAS) questions during the first antenatal care visit. The association of maternal history of dysmenorrhea and LBW was evaluated using logistic regression analyses adjusted for confounding factors (infant sex, maternal age, parity, pre-pregnancy body mass index (BMI) (kg/m²), gestational age, alcohol use during pregnancy, passive smoking, and occupational status).

RESULTS

Mothers with a history of dysmenorrhea were more likely to give birth to LBW infants (adjusted odds ratio (OR)=1.44; 95% confidence interval (CI): 1.12, 1.83). Among women with a history of dysmenorrhea, women ≥29 years old (adjusted OR 1.46; 95% CI 1.02, 2.10), multiparous (adjusted OR 1.59, 95% CI 1.12, 2.25), and women gave birth to female infant (adjusted OR = 1.53, 95% CI = 1.11, 2.11) had a higher risk of LBW.

CONCLUSIONS

As the first cohort study to investigate the association between maternal history of dysmenorrhea and LBW, our study shows that dysmenorrhea may increase the risk of LBW.

Risk Factors for Adverse Pregnancy Outcomes among Zhuang Ethnic Pregnant Women: A Cohort Study in Guangxi, China

Risk factors for adverse pregnancy outcomes among Zhuang ethnic pregnant women are unclear. This study analyzed the incidence and risk factors related to preterm birth (PB), low birth weight (LBW) and macrosomia in Zhuang population. We conducted a prospective cohort study of 9965 Zhuang pregnancy women in Guangxi, China. Information on mothers and newborns was obtained by using questionnaires and referring to medical records. Multivariate logistic regression analyses were used to evaluate the association between related factors and adverse pregnancy outcomes. Our results showed that the incidence of PB, LBW and macrosomia in Zhuang people was 5.55%, 5.64% and 2.19%, respectively. Maternal age ≥36 years (OR=2.22, 95% CI: 1.51-3.27) was related to a higher incidence of PB. Those with pre-pregnancy body mass index (BMI) <18.5 kg/m2 (OR=1.91, 95% CI: 1.45-2.51), and had a female fetus (OR=1.74, 95% CI: 1.36-2.23) were more likely to have LBW infants. Maternal age between 31 and 35 years (OR=1.76, 95% CI: 1.03-2.99) and pre-pregnancy overweight or obesity (OR=1.79, 95% CI: 1.15-2.80) were associated with a higher risk of macrosomia. The protective factors of macrosomia were maternal pre-pregnancy BMI <18.5 kg/m2 (OR=0.30, 95% CI: 0.15-0.60) and female fetus (OR=0.41, 95% CI: 0.28-0.59). Our study provided a reference for maternal and childcare administration among Zhuang population.

Prenatal exposure to multiple metals and birth outcomes: An observational study within the National Children's Study cohort

BACKGROUND

Prenatal exposure to metals may play an important role in fetal growth. However, the epidemiologic evidence for certain metals is sparse, and most of the existing research has focused on evaluating single metals in highly exposed target populations.

OBJECTIVES

We evaluated associations of cadmium, lead, manganese, selenium, and total mercury exposures during pregnancy with fetal growth using data from mother-infant pairs participating in the National Children's Study.

METHODS

Prenatal metal exposures were measured using maternal blood collected from 6 to 32 weeks of gestation. Birth outcomes, including gestational age, birthweight, birth length, head circumference, and ponderal index, were ascertained through physical measurement at birth or abstraction from medical records. Regression coefficients and their 95% confidence intervals were estimated from multivariable linear regression models in the overall study population as well as among male and female infants. We further evaluated pairwise metal-metal interactions.

RESULTS

Sex-specific associations were observed for lead, with inverse associations for birthweight, birth length, head circumference, and gestational age observed only among female infants. Sex-specific associations were also observed for selenium, with a positive association for birthweight observed among male infants; selenium was also positively associated with ponderal index and inversely associated with birth length among female infants. Overall, total mercury was inversely associated with birthweight and ponderal index, and the association with birthweight was stronger among female infants. No significant associations were observed with cadmium and manganese. In the metal-metal interaction analyses, we found evidence of a synergistic interaction between lead and total mercury and antagonistic interaction between selenium and total mercury with selected birth outcomes.

CONCLUSIONS

Our findings suggest that prenatal exposure to metals may be related to birth outcomes, and infant sex may modify these associations.

The impact of socioeconomic position (SEP) on women's health over the lifetime

The "social gradient of health" refers to the steep inverse associations between socioeconomic position (SEP) and the risk of premature mortality and morbidity. In many societies, due to cultural and structural factors, women and girls have reduced access to the socioeconomic resources that ensure good health and wellbeing when compared with their male counterparts. Thus, the objective of this paper is to review how SEP - a construct at the heart of the Social Determinants of Health (SDoH) theory - shapes the health and longevity of women and girls at all stages of the lifespan. Using literature identified from PubMed, Cochrane, CINAHL and EMBASE databases, we first describe the SDoH theory. We then use examples from each stage of the life course to demonstrate how SEP can differentially shape girls' and women's health outcomes compared with boys' and men's, as well as between sub-groups of girls and women when other axes of inequalities are considered, including ethnicity, race and residential setting. We also explore the key consideration of whether conventional SEP markers are appropriate for understanding the social determinants of women's health. We conclude by making key recommendations in the context of clinical, research and policy development.

Predicting risk of low birth weight offspring from maternal features and blood polycyclic aromatic hydrocarbon concentration

Prenatal exposure to organic pollutants increases the risk of low birth weight (LBW) offspring. Women involved in the plucking of tea leaves can be exposed to polycyclic aromatic hydrocarbons (PAHs) during pregnancy through inhalation and diet. Therefore, the aim of the study was to investigate the association of maternal socio-demographic features and blood PAH concentration with LBW; also to develop a model for predicting LBW risk. The study was performed by recruiting 55 women who delivered LBW and 120 women with NBW (normal birth weight) babies from Assam Medical College. The placental tissue, maternal and cord blood samples were collected. A total of sixteen PAHs and cotinine were analysed by HPLC and GC-MS. Association of PAH concentration with weight was determined using correlation and multiple logistic regression analyses. Predictive model was developed using SVM^light and Weka software. Maternal features such as age, education, food habits, occupation, etc. were found to be associated with LBW deliveries (p-value<0.05). Overall, 9 PAHs and cotinine were detected in the samples. A multiple logistic regression depicted an increased likelihood of LBW by exposure to PAHs (pyrene, di-benzo (a,h) anthracene, fluorene and fluoranthene) and cotinine. Models based on the features and PAHs/ cotinine predicted LBW offspring with 84.35% sensitivity and 74% specificity. LBW prediction models are available at http://dev.icmr.org.in/plbw/ webserver. With machine learning gaining more importance in medical science; our webserver could be instrumental for researchers and clinicians to predict the state of the fetus.

Exposure to Gestational Diabetes Is a Stronger Predictor of Dysmetabolic Traits in Children Than Size at Birth

CONTEXT AND OBJECTIVE

Being born small or large for gestational age and intrauterine exposure to gestational diabetes (GDM) increase the risk of type 2 diabetes in the offspring. However, the potential combined deleterious effects of size at birth and GDM exposure remains unknown. We examined the independent effect of size at birth and the influence of GDM exposure in utero on cardiometabolic traits, body composition, and puberty status in children.

DESIGN, PARTICIPANTS, AND METHODS

The present study was a longitudinal birth cohort study. We used clinical data from 490 offspring of mothers with GDM and 527 control offspring aged 9 to 16 years, born singleton at term from the Danish National Birth Cohort with available birthweight data.

RESULTS

We found no evidence of a U-shaped association between size at birth (expressed as birthweight, sex, and gestational age adjusted z-score) and cardiometabolic traits. Body size in childhood and adolescence reflected the size at birth but was not reflected in any metabolic outcome. No synergistic adverse effect of being born small or large for gestational age and exposure to GDM was shown. However, GDM was associated with an adverse metabolic profile and earlier onset of female puberty in childhood and adolescence independently of size at birth.

CONCLUSION

In childhood and adolescence, we found GDM was a stronger predictor of dysmetabolic traits than size at birth. The combination of being born small or large and exposed to GDM does not exacerbate the metabolic profile in the offspring.

Pregnant Inuit Women's Exposure to Metals and Association with Fetal Growth Outcomes: ACCEPT 2010⁻2015

Environmental contaminants such as heavy metals are transported to the Arctic regions via atmospheric and ocean currents and enter the Arctic food web. Exposure is an important risk factor for health and can lead to increased risk of a variety of diseases. This study investigated the association between pregnant women's levels of heavy and essential metals and the birth outcomes of the newborn child. This cross-sectional study is part of the ACCEPT birth cohort (Adaption to Climate Change, Environmental Pollution, and dietary Transition) and included 509 pregnant Inuit women ≥18 years of age. Data were collected in five Greenlandic regions during 2010⁻2015. Population characteristics and birth outcomes were obtained from medical records and midwives, respectively, and blood samples were analyzed for 13 metals. Statistical analysis included one-way ANOVA, Spearman's rho, and multiple linear and logistic regression analyses. The proportion of current smokers was 35.8%. The levels of cadmium, chromium, and nickel were higher compared to reported normal ranges. Significant regional differences were observed for several metals, smoking, and parity. Cadmium and copper were significantly inversely related to birth outcomes. Heavy metals in maternal blood can adversely influence fetal development and growth in a dose⁻response relationship. Diet and lifestyle factors are important sources of toxic heavy metals and deviant levels of essential metals. The high frequency of smokers in early pregnancy is of concern, and prenatal exposure to heavy metals and other environmental contaminants in the Greenlandic Inuit needs further research.

Vomiting in pregnancy is associated with a higher risk of low birth weight: a cohort study

BACKGROUND

Low birth weight has important short- and long-term health implications. Previously it has been shown that pregnancies affected by hyperemesis gravidarum in the mother are at higher risk of having low birth weight offspring. In this study we tested whether such risks are also evident with less severe nausea and vomiting in pregnancy.

METHODS

One thousand two hundred thirty-eight women in the prospective Cambridge Baby Growth Study filled in pregnancy questionnaires which included questions relating to adverse effects of pregnancy and drugs taken during that time. Ordinal logistic regression models, adjusted for parity, ethnicity, marital and smoking status were used to relate the risk of giving birth to low birth weight (< 2.5 kg) babies to nausea and/or vomiting in pregnancy that were not treated with anti-emetics and did not report suffering from hyperemesis gravidarum.

RESULTS

Only three women in the cohort reported having had hyperemesis gravidarum although a further 17 women reported taking anti-emetics during pregnancy. Of those 1218 women who did not take anti-emetics 286 (23.5%) did not experience nausea or vomiting, 467 (38.3%) experienced nausea but not vomiting and 465 experienced vomiting (38.2%). Vomiting during pregnancy was associated with higher risk of having a low birth weight baby (odds ratio 3.5 (1.2, 10.8), p = 0.03). The risk associated with vomiting was found in the first (p = 0.01) and second (p = 0.01) trimesters but not the third (p = 1.0). The higher risk was not evident in those women who only experienced nausea (odds ratio 1.0 (0.3, 4.0), p = 1.0).

CONCLUSIONS

Vomiting in early pregnancy, even when not perceived to be sufficiently severe to merit treatment, is associated with a higher risk of delivering a low birth weight baby. Early pregnancy vomiting might therefore be usable as a marker of higher risk of low birth weight in pregnancy. This may be of benefit in situations where routine ultrasound is not available to distinguish prematurity from fetal growth restriction, so low birth weight is used as an alternative.

Low alcohol consumption and pregnancy and childhood outcomes: time to change guidelines indicating apparently 'safe' levels of alcohol during pregnancy? A systematic review and meta-analyses

OBJECTIVES

To determine the effects of low-to-moderate levels of maternal alcohol consumption in pregnancy on pregnancy and longer-term offspring outcomes.

SEARCH STRATEGY

Medline, Embase, Web of Science and Psychinfo from inception to 11 July 2016.

SELECTION CRITERIA

Prospective observational studies, negative control and quasiexperimental studies of pregnant women estimating effects of light drinking in pregnancy (≤32 g/week) versus abstaining. Pregnancy outcomes such as birth weight and features of fetal alcohol syndrome were examined.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data and another checked extracted data. Random effects meta-analyses were performed where applicable, and a narrative summary of findings was carried out otherwise.

MAIN RESULTS

24 cohort and two quasiexperimental studies were included. With the exception of birth size and gestational age, there was insufficient data to meta-analyse or make robust conclusions. Odds of small for gestational age (SGA) and preterm birth were higher for babies whose mothers consumed up to 32 g/week versus none, but estimates for preterm birth were also compatible with no association: summary OR 1.08, 95% CI (1.02 to 1.14), I² 0%, (seven studies, all estimates were adjusted) OR 1.10, 95% CI (0.95 to 1.28), I² 60%, (nine studies, includes one unadjusted estimates), respectively. The earliest time points of exposure were used in the analysis.

CONCLUSION

Evidence of the effects of drinking ≤32 g/week in pregnancy is sparse. As there was some evidence that even light prenatal alcohol consumption is associated with being SGA and preterm delivery, guidance could advise abstention as a precautionary principle but should explain the paucity of evidence.

Cumulative effects of prenatal-exposure to exogenous chemicals and psychosocial stress on fetal growth: Systematic-review of the human and animal evidence

BACKGROUND

Adverse effects of prenatal stress or environmental chemical exposures on fetal growth are well described, yet their combined effect remains unclear.

OBJECTIVES

To conduct a systematic review on the combined impact and interaction of prenatal exposure to stress and chemicals on developmental outcomes.

METHODS

We used the first three steps of the Navigation Guide systematic review. We wrote a protocol, performed a robust literature search to identify relevant animal and human studies and extracted data on developmental outcomes. For the most common outcome (fetal growth), we evaluated risk of bias, calculated effect sizes for main effects of individual and combined exposures, and performed a random effects meta-analysis of those studies reporting on odds of low birthweight (LBW) by smoking and socioeconomic status (SES).

RESULTS

We identified 17 human- and 22 animal-studies of combined chemical and stress exposures and fetal growth. Human studies tended to have a lower risk of bias across nine domains. Generally, we found stronger effects for chemicals than stress, and these exposures were associated with reduced fetal growth in the low-stress group and the association was often greater in high stress groups, with limited evidence of effect modification. We found smoking associated with significantly increased odds of LBW, with a greater effect for high stress (low SES; OR 4.75 (2.46-9.16)) compared to low stress (high SES; OR 1.95 (95% CI 1.53-2.48)). Animal studies generally had a high risk of bias with no significant combined effect or effect modification.

CONCLUSIONS

We found that despite concern for the combined effects of environmental chemicals and stress, this is still an under-studied topic, though limited available human studies indicate chemical exposures exert stronger effects than stress, and this effect is generally larger in the presence of stress.

Maternal risk exposure during pregnancy and infant birth weight

BACKGROUND

Birth weight is an important determinant of an infant's immediate and future health.

AIM

This study examined associations between selected maternal psychosocial and environmental risk factors during pregnancy and subsequent infant birth weight, utilising data from the South African Birth to Twenty Plus (Bt20+) birth cohort study.

SUBJECTS

Exposure to nine maternal risks were assessed in 1228 women who completed an antenatal questionnaire and whose infants were delivered within a seven-week period.

OUTCOME MEASURES

The outcome of interest was infant birth weight. Birth weight z-scores (BWZ) were calculated using the World Health Organization Child Growth Standards. Bivariate analyses and multiple regression models were used to identify significant risk factors.

RESULTS

The mean infant birth weight was 3139g (SD 486g), with a significant advantage in mean birth weight for male infants of 73g (p=0.008). Being unsure or not wanting the pregnancy was associated with a ~156g reduction in infant birth weight (β=-0.32; 95% CI -0.51; -0.14). Tobacco use during pregnancy was also negatively associated with BWZ (β=-0.32; 95% CI -0.59; -0.05). Exposure to both significant risk factors (tobacco use and pregnancy wantedness) was associated with cumulative reductions in birth weight, particularly among boys.

CONCLUSIONS

This study reinforces the importance of risks related to maternal attitudes and behaviours during pregnancy, namely unwanted pregnancy and tobacco use, which significantly lowered birth weight. Both identified risks are amenable to public health policy and programme intervention.

Does Maternal Country of Birth Matter for Understanding Offspring's Birthweight? A Multilevel Analysis of Individual Heterogeneity in Sweden

Background

Many public health and epidemiological studies have found differences between populations (e.g. maternal countries of birth) in average values of a health indicator (e.g. mean offspring birthweight). However, the approach based solely on population-level averages compromises our understanding of variability in individuals’ health around the averages. If this variability is high, the exclusive study of averages may give misleading information. This idea is relevant when investigating country of birth differences in health.

Methods and Results

To exemplify this concept, we use information from the Swedish Medical Birth Register (2002–2010) and apply multilevel regression analysis of birthweight, with babies (n = 811,329) at the first, mothers (n = 571,876) at the second, and maternal countries of birth (n = 109) at the third level. We disentangle offspring, maternal and maternal country of birth components of the total offspring heterogeneity in birthweight for babies born within the normal timespan (37–42 weeks). We found that of such birthweight variation about 50% was at the baby level, 47% at the maternal level and only 3% at the maternal countries of birth level.

Conclusion

In spite of seemingly large differences in average birthweight among maternal countries of birth (range 3290–3677g), knowledge of the maternal country of birth does not provide accurate information for ascertaining individual offspring birthweight because of the high inter-offspring heterogeneity around country averages. Our study exemplifies the need for a better understanding of individual health diversity for which group averages may provide insufficient and even misleading information. The analytical approach we outline is therefore relevant to investigations of country of birth (and ethnic) differences in health in general.

Low birth weight at term and its determinants in a tertiary hospital of Nepal: a case-control study

Birth weight of a child is an important indicator of its vulnerability for childhood illness and chances of survival. A large number of infant deaths can be averted by appropriate management of low birth weight babies and prevention of factors associated with low birth weight. The prevalence of low birth weight babies in Nepal is estimated to be about 12-32%.Our study aimed at identifying major determinants of low birth weight among term babies in Nepal. A hospital-based retrospective case control study was conducted in maternity ward of Tribhuvan University Teaching Hospital from February to July 2011. A total of 155 LBW babies and 310 controls were included in the study. Mothers admitted to maternity ward during the study period were interviewed, medical records were assessed and anthropometric measurements were done. Risk factors, broadly classified into proximal and distal factors, were assessed for any association with birth of low-birth weight babies. Regression analysis revealed that a history of premature delivery (adjusted odds ratio; aOR5.24, CI 1.05-26.28), hard physical work during pregnancy (aOR1.48, CI 0.97-2.26), younger age of mother (aOR1.98, CI 1.15-3.41), mothers with haemoglobin level less than 11gm/dl (aOR0.51, CI0.24-1.07) and lack of consumption of nutritious food during pregnancy (aOR1.99, CI 1.28-3.10) were significantly associated with the birth of LBW babies. These factors should be addressed with appropriate measures so as to decrease the prevalence of low birth weight among term babies in Nepal.

[Study of low birth weight associated with maternal age and parity in a population of mother and children in Lubumbashi]

Introduction

Evaluer l'influence de l’âge maternel et de la parité sur la naissance d'un faible poids de naissance (FPN) à Lubumbashi.

Méthodes

Il s'agit d'une étude basée sur une analyse documentaire des dossiers médicaux des accouchées enregistrées dans les maternités des 10 hôpitaux généraux de référence (HGR) de la ville de Lubumbashi en République Démocratique du Congo entre le 1er décembre 2013 et le 31 mars 2014. Ces accouchées ont été réparties en deux groupes, en fonction du poids de naissance de leurs enfants: groupe I (femmes ayant accouché de nouveau-nés vivants dont le poids était inférieur à 2500 grammes) et groupe II (femmes ayant accouché de nouveau-nés vivants dont le poids était supérieur ou égal à 2500 grammes). Il s'agissait dans tous les cas de grossesses monofoetales âgées de 28 semaines ou plus. L’âge maternel et la parité ont été étudiés et comparés dans les deux groupes. Les données ont été analysées à l'aide des logiciels Épi info version 7.0 et SPSS version 19. Les différences étaient jugées significatives pour un seuil p < 0,05.

Résultats

La prévalence du FPN chez les nouveau-nés issus de ces accouchées était ainsi de 6,4% (71/1112). En analyse univariée, les femmes d’âge < 20 ans présentent un risque multiplié par 2,47 fois d'avoir un nouveau-né de FPN comparativement à celles de ≥20 ans (OR = 2,47; IC95%: 1,26-4,78) et celui pour les primipares d'avoir un enfant de FPN est 2,3 fois supérieur à celui de multipares (OR = 2,32; IC95%: 1,34-3,99). En faisant la régression logistique, nous avons observé que seule la parité est significativement corrélée au poids de naissance (OR ajusté = 2,61; IC95%: 1,43-4,74).

Conclusion

L’étude que nous avons menée montre que le taux de FPN diminue considérablement avec l’âge de la mère à partir de 20 ans et la multiparité.

Mediation analysis of gestational age, congenital heart defects, and infant birth-weight

BACKGROUND

In this study we assessed the mediation role of the gestational age on the effect of the infant's congenital heart defects (CHD) on birth-weight.

METHODS

We used secondary data from the Baltimore-Washington Infant Study (1981-1989). Mediation analysis was employed to investigate whether gestational age acted as a mediator of the association between CHD and reduced birth-weight. We estimated the mediated effect, the mediation proportion, and their corresponding 95% confidence intervals (CI) using several methods.

RESULTS

There were 3362 CHD cases and 3564 controls in the dataset with mean birth-weight of 3071 (SD = 729) and 3353 (SD = 603) grams, respectively; the mean gestational age was 38.9 (SD = 2.7) and 39.6 (SD = 2.2) weeks, respectively. After adjusting for covariates, the estimated mediated effect by gestational age was 113.5 grams (95% CI, 92.4-134.2) and the mediation proportion was 40.7% (95% CI, 34.7%-46.6%), using the bootstrap approach.

CONCLUSIONS

Gestational age may account for about 41% of the overall effect of heart defects on reduced infant birth-weight. Improved prenatal care and other public health efforts that promote full term delivery, particularly targeting high-risk families and mothers known to be carrying a fetus with CHD, may therefore be expected to improve the birth-weight of these infants and their long term health.

Correlates of Low Birth Weight

Background. Low birth weight is the single most important factor that determines the chances of child survival. A recent annual estimation indicated that nearly 8 million infants are born with low birth weight in India. The infant mortality rate is about 20 times greater for all low birth weight babies. Methods. A matched case–control study was conducted on 130 low birth weight babies and 130 controls for 12 months (from August 1, 2007, to July 31, 2008) at the Central Referral Hospital, Tadong, East District of Sikkim, India. Data were analyzed using the Statistical Package for Social Sciences, version 10.0 for Windows. Chi-square test and multiple logistic regression were applied. A P value less than .05 was considered as significant. Results. In the first phase of this study, 711 newborn babies, borne by 680 mothers, were screened at the Central Referral Hospital of Sikkim during the 1-year study period, and the proportion of low birth weight babies was determined to be 130 (18.3%). Conclusion. Multiple logistic regression analysis, conducted in the second phase, revealed that low or middle socioeconomic status, maternal underweight, twin pregnancy, previous history of delivery of low birth weight babies, smoking and consumption of alcohol during pregnancy, and congenital anomalies had independent significant association with low birth weight in this study population.

Young maternal age and low birth weight risk: An exploration of racial/ethnic disparities in the birth outcomes of mothers in the United States

This study considers how low birth weight (LBW) prevalence varies by race/ethnicity and maternal age and explores mechanisms that explain disparities. Results show that maternal age patterns in LBW risk for African Americans differ from whites and foreign- and U.S.-born Hispanics. Background socioeconomic disadvantage, together with current socioeconomic status and smoking during pregnancy, explain almost all of the LBW disparity between white teenage mothers and their older counterparts. These findings suggest that social disadvantage is a primary driver in unfavorable birth outcomes among white teenage mothers compared to older white mothers. Alternatively, background disadvantage and other social characteristics explain very little of the LBW disparities among African Americans and U.S.- and foreign-born Hispanics. Overall, these results indicate LBW disparities by maternal age are a complex product of socioeconomic disadvantage and current social and behavioral factors, such that LBW risk does not operate uniformly by race/ethnicity or maternal age.

Neighborhood adversity, ethnic diversity, and weak social cohesion and social networks predict high rates of maternal depressive symptoms: a critical realist ecological study in South Western Sydney, Australia

The aim of the study reported here is to explore ecological covariate and latent variable associations with perinatal depressive symptoms in South Western Sydney for the purpose of informing subsequent theory generation of perinatal context, depression, and the developmental origins of health and disease. Mothers (n = 15,389) delivering in 2002 and 2003 were assessed at two to three weeks after delivery for risk factors for depressive symptoms. The binary outcome variables were Edinburgh Postnatal Depression Scale (EPDS)> 9 and > 12. Aggregated EPDS > 9 was analyzed for 101 suburbs. Suburb-level variables were drawn from the 2001 Australian Census, New South Wales Crime Statistics, and aggregated individual-level risk factors. Analysis included exploratory factor analysis, univariate and multivariate likelihood, and Bayesian linear regression with conditional autoregressive components. The exploratory factor analysis identified six factors: neighborhood adversity, social cohesion, health behaviors, housing quality, social services, and support networks. Variables associated with neighborhood adversity, social cohesion, social networks, and ethnic diversity were consistently associated with aggregated depressive symptoms. The findings support the theoretical proposition that neighborhood adversity causes maternal psychological distress and depression within the context of social buffers including social networks, social cohesion, and social services.

Neighborhood inequalities in adverse pregnancy outcomes in an urban setting in Spain: a multilevel approach

The aim of the present study was to describe socioeconomic inequalities in low birth weight (LBW), premature birth (PM) and small size for gestational age at birth (SGA) between 2000 and 2005 in Barcelona, Spain, jointly evaluating the effect of mother's country of origin, and neighborhood of residence socioeconomic level measured using unemployment and educational level. We performed a cross-sectional study of births to mothers aged 12-49 years who were residents in the city of Barcelona in 2000-2005, analyzing adverse pregnancy outcomes (n = 61,676). Weighted multilevel logistic regression models were fitted with individual data on level 1 and neighborhood data on level 2, to obtain adjusted odds ratios (aOR) with 95% confidence intervals and residual variance. Individually, pregnancy outcomes are more favorable in births to older mothers and to mothers from Maghrib and Central and South America than from developed countries (including Spain) or from other developing countries. After adjusting for individual variables, poor pregnancy outcomes were associated with poor neighborhoods (more unemployment was associated to LBW: aOR = 1.56; PM aOR = 1.51; SGA aOR = 1.66). The same trend was observed for associations with illiteracy rate. The present study shows that there are socioeconomic inequalities in adverse pregnancy outcomes in the city of Barcelona. One of the main challenges in perinatal health continues to be the reduction of adverse pregnancy outcomes in the city.

Maternal active smoking and newborn body composition

OBJECTIVE

Maternal smoking during pregnancy is associated with a reduction in birth size but very few studies have collated changes in neonatal anthropometry. Our aims were both to assess body composition differences by anthropometry between new-borns from smoking mothers and those from non-smoking mothers, and to show whether these differences affect proportional body mass distribution.

METHODS

Caucasian mothers and their full term singleton new-borns (N=1216) were selected during 2009. A structured questionnaire was completed regarding obstetric and demographic data, as well as tobacco consumption. Women were categorized, according to their smoking habits, into a non-smoking group (never smoked or stopped smoking prior to pregnancy) and a smoking group (smoked throughout pregnancy).

RESULTS

22.1% of mothers smoked during pregnancy (median: 6 cigarettes/day, range: l-40). Smoking mothers were significantly younger than non-smoking mothers but there were no differences regarding other aspects which could affect infant weight. Infants from non-smoking mothers were heavier, longer, and body circumferences were all larger than those from smoking mothers (p<0.001), but the Ponderal Index showed no statistical differences. Skinfold thicknesses were significantly lower in new-borns from smoking mothers but these differences were less evident than those from body size. Subcutaneous fat distribution did not show statistical differences between the two groups. After gestational age, to smoke during gestation is the second main determinant of birth weight.

CONCLUSIONS

Smoking during pregnancy involves a generalized reduction of most axiological parameters as a result of proportionate fetal growth impairment. In those infants born from mothers who smoked during gestation, neonatal lean body mass appears to be more affected than body fat, and distribution of subcutaneous fat is not different.

Postnatal depression and socio-demographic risk: factors associated with Edinburgh Depression Scale scores in a metropolitan area of New South Wales, Australia

OBJECTIVE

The aim of this study was to determine the prevalence and risk factors for postnatal depressive symptoms in women living in metropolitan Sydney, Australia.

METHOD

A population-based cross-sectional study of mothers of newborn infants was undertaken during home and community clinic visits in South West Sydney from 2000 to 2004. A comprehensive 45 item survey questionnaire was completed by 29 405 mothers. A self-report Edinburgh Postnatal Depression Scale (EPDS) of depressive symptoms was completed by 25 455 mothers at the first child and family nurse visit. The primary study outcome measures were EPDS scores greater than 9 and greater than 12.

RESULTS

At a mean infant age of 2.16 weeks the prevalence of EPDS >9 was 12% and EPDS >12 was 6.2%. Results from multiple logistic regression revealed that EPDS >9 and EPDS > 2 were associated with a maternal country of birth other than Australia, difficult financial situation, living in the suburb one year or less, 'no regret leaving the suburb', unplanned pregnancy, not breastfeeding, and poor rating of mother's own health. Other social demographic factors such as marital status, maternal age, education of mother, or being Aboriginal or a Torres Strait Islander show no significant association with postnatal depressive symptoms.

CONCLUSIONS

The results confirm prevalence rates and maternal individual-level risk factors from previous studies. The study contributes to the limited number of studies of postnatal depression and socio-demographic factors. Neighbourhood and community group-level factors may be important and should be studied further.

Maternal smoking during pregnancy among Aboriginal women in New South Wales is linked to social gradient

OBJECTIVE

Social gradients in Aboriginal health are seldom explored. This study describes social gradients and trends in smoking during pregnancy among Aboriginal mothers in NSW.

METHODS

This was a secondary analysis of the NSW Midwives Data Collection (MDC) 1994-2007, covering all births in NSW. Analyses examined associations between socio-demographic characteristics and smoking during pregnancy.

RESULTS

Data from 1,214,206 pregnant women showed that 17.4% smoked during pregnancy. The rate of smoking during pregnancy among all NSW women declined from 22.3% in 1994 to 12.8% in 2007; the rate among Aboriginal women remained high, declining from 61.4% in 1994 to 50.2% in 2007. Smoking was substantially higher among Aboriginal mothers compared to non-Aboriginal mothers. Socio-economic analyses showed that the smoking rate among low SES Aboriginal mothers was approximately two and a half times that of high SES Aboriginal women, a similar gradient to non-Aboriginal women.

CONCLUSIONS

Indicators of socio-economic position are a consistent, independent correlate of smoking during pregnancy for Aboriginal and non-Aboriginal women.

IMPLICATIONS

There is a need for a social inequalities approach to smoking during pregnancy, specifically targeting more disadvantaged Aboriginal mothers and all teenage mothers for smoking prevention. Strategies to access more disadvantaged mothers should not be missed through broadly focused Aboriginal tobacco control strategies.

Improved pregnancy outcome in refugees and migrants despite low literacy on the Thai-Burmese border: results of three cross-sectional surveys

BACKGROUND

Maternal and infant health has been associated with maternal education level, which is highly associated with literacy. We aimed at estimating literacy rates among reproductive age women attending antenatal clinics in camps for refugees and in migrant clinics in Tak province, north-western Thailand, to determine whether illiteracy had an impact on birth outcomes.

METHODS

Three reading assessments were conducted using an identical method each time, in 1995-97, 2003 and 2008. Midwives chose at random one of four pre-set sentences. Each woman was asked to read aloud and scoring was based on a "pass/fail" system. Pregnancy outcomes were compared with maternal literacy rate.

RESULTS

Overall, 47% (1149/2424) of women were able to read. A significant improvement was observed among migrant (34% in 2003 vs. 46% in 2008, p = 0.01), but not refugee (47% in 1995-97, 49% in 2003, and 51% in 2008) women. Literate women were significantly more likely to be of non-Karen ethnicity, primigravidae, non-smokers, to remain free from malaria during pregnancy and to deliver in a health clinic. Significant improvements in pregnancy outcome (reductions in premature births, low birth weight newborns and neonatal death) between 1995-97 and 2003 were unrelated to literacy.

CONCLUSIONS

Significant reductions in poor pregnancy outcome over time have not been driven by changes in literacy rates, which have remained low. Access to early diagnosis and treatment of malaria in this population, and delivery with skilled birth attendants, despite ongoing low literacy, appears to have played a significant role.

Association of Low Birth Weight Infants and Maternal Sociodemographic Status in Tuzla Canton during 1992-1995 War Period in Bosnia and Herzegovina

Objectives. We examined association between incidence rate of low birth weight in liveborn infants and maternal sociodemographic status in Tuzla Canton during 1992–1995 war in Bosnia and Herzegovina. Methods. The present study covers a 22-year period (1988–2009), including the war period (1992–1995), and we retrospectively collected data on a total of 108 316 liveborn infants and their mothers from three different socioeconomic periods: before (1988–1991), during (1992–1995), and after the war (1996–2009). Association between incidence rate of low birth weight in liveborn infants and maternal sociodemographic status were determined for each study period. Results. There were 23 194 live births in the prewar, 18 302 during the war, and 66 820 in the postwar period. Among the liveborn infants born during the war, 1373 (7.5%) had birth weight of <2500 g, which is significantly more in comparison with 851 (3.6%) liveborn infants in this birth weight group born before and 1864 (2.8%) after the war. We found the number of examinations during pregnancy was 1.8 per pregnant woman in the war period, which was low in comparison with the number of examinations before (4.6 per pregnant woman) and after (7.1 per pregnant woman) the war (P<.001 for both). Prewar perinatal mortality LBW infants of 6.2 per 1000 live births increased to 10.8 per 1000 live births during the war (P<.001), but after the war, perinatal mortality LBW infants (5.2‰) and early neonatal mortality (2.4‰) decreased. Conclusions. We found statistically significant association between low-birth-weight and maternal sociodemographic status in Tuzla Canton during 1992–1995 war in Bosnia and Herzegovina.

Urban trees and the risk of poor birth outcomes

This paper investigated whether greater tree-canopy cover is associated with reduced risk of poor birth outcomes in Portland, Oregon. Residential addresses were geocoded and linked to classified-aerial imagery to calculate tree-canopy cover in 50, 100, and 200 m buffers around each home in our sample (n=5696). Detailed data on maternal characteristics and additional neighborhood variables were obtained from birth certificates and tax records. We found that a 10% increase in tree-canopy cover within 50 m of a house reduced the number of small for gestational age births by 1.42 per 1000 births (95% CI-0.11-2.72). Results suggest that the natural environment may affect pregnancy outcomes and should be evaluated in future research.

Relationship between parental knowledge of fetal gender and newborns' birthweight among Jordanian families

The purpose of this study was to examine the relationship between women knowing the fetal gender and their newborns' birthweight. Four-hundred and eighty-four post-partum mothers before discharge from the maternity unit participated in this study. We collected our data from the women by using two sources: a demographic data questionnaire and reviews of hospital records. For this study, we considered normal birthweight as > 2500 and < 4000 g and low birthweight as < 2500 g. The findings of the study suggested that knowledge of fetal gender was significantly related to the mean birthweight of newborns. When the gender was known prenatally, the mean birthweight of male newborns was significantly higher than that of female newborns. Also knowledge of fetal gender was found to increase the probability of low birthweight among female newborns compared with male newborns. Identifying sociocultural factors that might be linked to the gender preference could improve mothers' and their newborns' well-beings. Nurses have to be aware of the consequences of gender preference such as low birthweight.

Acute effect of cigarette smoking on placental circulation - a study by carbon-monoxide measurement and Doppler assessment

OBJECTIVE

Carbon-monoxide (CO) decreases placental vascular impedance. We assessed the consequences of smoking-induced temporary maternal CO-increase on fetal and placental circulation.

STUDY DESIGN

In a prospective study twenty-nine smoking pregnant women and their fetuses were evaluated. We determined the changes in maternal blood CO levels after smoking, and the concomitant changes in maternal and fetal circulation. Changes in fetal heart rate, uterine artery (UTA), middle cerebral artery (MCA), and descending aorta (DA) flow were measured by Doppler velocimetry. Changes in maternal CO level and umbilical flow value were assessed by paired t-test. The correlation between CO level and placental flow was assessed by partial correlation test.

RESULTS

CO level increased (mean +/-SD 1.7 +/- 0.065% vs. 2.36 +/- 0.89, p<0.0001). Nicotine-related maternal circulatory parameters changed significantly, but uterine flow values remained unchanged. Fetal heart rate increased, while flow in MCA and DA showed no change. CO-dependent umbilical artery impedance remained unchanged (Pulsatility Index: 0.956 +/- 0.18 vs. 0.948 +/- 0.21). Partial correlation between CO level and umbilical arterial impedance showed no significance (r:-0.324).

CONCLUSION

Despite significant CO elevation, the mainly CO-regulated placental flow remained unchanged.

Birth weight among singletons born to foreign-born mothers in Taiwan: a population-based birth register study

BACKGROUND

We compared the birth weight of newborns born to foreign-born mothers (FBMs) and Taiwan-born mothers (TBMs), using data from the 2005-2006 Taiwan Birth Registry of singleton live births.

METHODS

The Wilcox-Russell method, data restriction, and multiple linear regression were used to analyze the data. The rates of low birth weight (<2500 g) with 95% confidence intervals were computed for TBMs, and for each of the nationalities of FBMs.

RESULTS

The mean birth weight of newborns of FBMs was 3157 g, which was higher than that of newborns of TBMs (3109 g). On analysis using the Wilcox-Russell method, both the rate and residual proportion of low-birth-weight (LBW) births were lower among newborns of FBMs (4.1% and 1.1%, respectively) than among newborns of TBMs (5.9% and 1.7%, respectively). After adjusting for sex, mode of delivery, maternal age, smoking status, predisposing maternal risk factors, and condition during pregnancy, the newborns of FBMs weighed 72.9 g (95% CI, 68.8 g to 77.0 g) more than the newborns of TBMs. When data were restricted to mothers without any adverse conditions and adjusted for maternal age, the differences in birth weight between the 2 groups remained unchanged. The rates of LBW deliveries among FBMs in Taiwan were significantly lower than those in their respective countries of origin.

CONCLUSIONS

In Taiwan, newborns of FBMs had a higher birth weight than those of TBMs, even after accounting for potential confounding factors, and had lower rates of LBW deliveries than did mothers in their respective countries of origin.

Women with intellectual disability at risk of adverse pregnancy and birth outcomes

BACKGROUND

An increasing number of women with intellectual disability (ID) have children. Cross-sectional, clinical population data suggest that these women face an increased risk of delivering preterm and/or low birthweight babies. The aim of this study was to explore the prevalence of poor pregnancy and birth outcomes in women with ID and/or self-reported learning difficulties in an antenatal population.

METHODS

A total of 878 pregnant women attending their first antenatal clinic visit were 'screened' for ID. Pregnancy and birth outcomes data were extracted from medical records post-partum. These data included pregnancy-related health conditions, including pre-eclampsia and gestational diabetes, and birth outcomes, including gestational age, birthweight, Apgar score and admission to neonatal intensive care and/or special care nursery.

RESULTS

A total of 57 (6.5%) pregnant women with ID and/or self-reported learning difficulties were identified. These women experienced an unusually high rate of pre-eclampsia (odds ratio = 2.85). Their children more often had low birthweights (odds ratio = 3.08), and they were more frequently admitted to neonatal intensive care or special care nursery (odds ratio = 2.51).

CONCLUSION

Further research is needed to understand the reasons for the adverse findings of this study and identify potentially changeable factors contributing to adverse pregnancy and birth outcomes for women with ID and/or self-reported learning difficulties and their children. To ensure quality antenatal care, health professionals may need to consider innovations such as extended consultation times, communication aids and audio-taping consultations.

Social influences for smoking in pregnancy in south western Sydney antenatal clinic attendees

This study examined the needs of and barriers to smoking cessation of 677 women who attended antenatal clinics in south-west Sydney. More than a quarter (26.3%) of the mothers reported smoking at their first antenatal visit. Smokers were more likely to be teenagers, single mothers and less likely to have formal education or employment. They were less aware of the potential health risks of smoking in pregnancy (SIP). High levels of SIP remain a public health problem, and effective interventions are needed.

Factors influencing breastfeeding rates in south-western Sydney

AIM

To explore the socio-demographic factors and other maternal characteristics that influence breastfeeding initiation rates. In particular, this paper aims to (i) estimate the rate of breastfeeding by maternal socio-demographic factors and other maternal characteristics at first well-baby visit; and (ii) investigate the relationship between breastfeeding rates and these maternal factors.

METHODS

Cross-sectional data were obtained for 9618 babies in south-western Sydney in New South Wales from the Ingleburn Baby Information Systems database from January 2000 to June 2004 and included information on breastfeeding status, socio-demographic factors and other maternal characteristics.

RESULTS

At first visit, 59.8% of mothers were breastfeeding. The factors that increased the risk for NOT breastfeeding on multivariate analysis were being Australian-born (OR=1.67, 95% CI 1.45-1.89, P<0.001), unmarried (OR=1.79, 95% CI 1.52-2.11, P<0.001), living in disadvantaged accommodation (OR=1.90, 95% CI 1.60-2.26, P<0.001), having lower levels of education (OR=1.88, 95% CI 1.38-2.54, P<0.001) and current smoking (OR=1.72, 95% CI 1.51-1.96, P<0.001).

CONCLUSION

The results from this large population-based study suggest that breastfeeding rates are significantly influenced by socio-demographic factors and maternal characteristics. Consequently, subgroups of the population 'at risk' for not breastfeeding can be identified and targeted for further strategies to promote breastfeeding.

Consumo de tabaco durante el embarazo en España: análisis por años, comunidades autónomas y características maternas

BACKGROUND AND OBJECTIVE

The information about the convenience of non-smoking during pregnancy has increased in recent years. For this reason, we studied weather there has been any variation in smoking habits by pregnant women in Spain.

SUBJECTS AND METHOD

We used data from 31,056 mothers of infants without congenital defects, from all the Spanish Autonomic Regions. These data had been collected with the same methodology all over the country. The evolution of maternal smoking habit was analyzed by years, Autonomic Regions and maternal characteristics.

RESULTS

During the last years of the study (1995-2002), 30.31% of mothers smoked during pregnancy, with variations among different ethnic groups. It was observed a secular increase in the prevalence of smoker mothers from 1978 to 1991, which was further stable in about 27-28%. There was no secular decrease in the analyses by maternal age, number of cigarettes, and Autonomic Regions. Only smoker mothers with higher educational levels diminished smoking in 1993, with it being stable in about 23%. Mothers younger than 25 years were the heaviest smokers in all the years of the study. We confirmed a close relationship between tobacco, alcohol and illegal drugs consumption.

CONCLUSIONS

Our data indicate that the prevalence of women smoking during pregnancy has not diminished over the years or by Autonomic Regions, although 19.19% of smoker pregnant women quit smoking during the first months of pregnancy. Moreover, the heaviest smoker mothers were the youngest ones in all the years of the study. These results show the need to increase the information for women so that they quit smoking before pregnancy.

Total protein concentration in human amniotic fluid is negatively associated with infant birth weight

Our objectives were 2-fold: 1) to assess the concentration and distribution of total protein in human amniotic fluid (AF) using 3 standard assays [Bradford, bicinchoninic acid solution (BCA), and Lowry] and 2) to establish whether these total protein concentrations were associated with and predictive of infant birth weight. Birth outcomes were determined using recently developed birth-weight-for-gestational-age categories (percentiles) for fetal growth where infants < 10% were classified as SGA (small-for-gestational-age), those between 10 and 90% as appropriate-for-gestational-age (AGA) and those infants >/= 90% as large-for-gestational-age (LGA). AF samples were collected from women undergoing routine amniocentesis for genetic testing (mean = 15 +/- 0.04 wk, range 12-20 wk), frozen, and later analyzed for total protein in 617 singleton-expectant mothers in Montréal, QC, Canada. Maternal and fetal characteristics were obtained from questionnaires and medical chart review. Mothers giving birth to LGA infants had uniformly lower AF protein concentrations at 12-20 wk gestation compared with AF protein concentrations for mothers of AGA infants. Multiple regression analyses demonstrated that total AF protein, collected during routine amniocentesis and later analyzed by the Lowry method, was negatively associated with birth weight at term in our population. These data suggest that one or more AF proteins might emerge as biomarkers of fetal growth.

Endocrine disruption by cadmium, a common environmental toxicant with paradoxical effects on reproduction

Cadmium (Cd(2+)) is a common environmental pollutant and a major constituent of tobacco smoke. Exposure to this heavy metal, which has no known beneficial physiological role, has been linked to a wide range of detrimental effects on mammalian reproduction. Intriguingly, depending on the identity of the steroidogenic tissue involved and the dosage used, it has been reported to either enhance or inhibit the biosynthesis of progesterone, a hormone that is inexorably linked to both normal ovarian cyclicity and the maintenance of pregnancy. Thus, Cd(2+) has been shown to exert significant effects on ovarian and reproductive tract morphology, with extremely low dosages reported to stimulate ovarian luteal progesterone biosynthesis and high dosages inhibiting it. In addition, Cd(2+) exposure during human pregnancy has been linked to decreased birth weights and premature birth, with the enhanced levels of placental Cd(2+) resulting from maternal exposure to industrial wastes or tobacco smoke being associated with decreased progesterone biosynthesis by the placental trophoblast. The stimulatory effects of Cd(2+) on ovarian progesterone synthesis, as revealed by the results of studies using stable porcine granulosa cells, appear centered on the enhanced conversion of cholesterol to pregnenolone by the cytochrome P450 side chain cleavage (P450scc). However, in the placenta, the Cd(2+)-induced decline in progesterone synthesis is commensurate with a decrease in P450scc. Additionally, placental low-density lipoprotein receptor (LDL-R) mRNA declines in response to Cd(2+) exposure, suggesting an inhibition in the pathway that provides cholesterol precursor from the maternal peripheral circulation. Potential mechanisms by which Cd(2+) may affect steroidogenesis include interference with the DNA binding zinc (Zn(2+))-finger motif through the substitution of Cd(2+) for Zn(2+) or by taking on the role of an endocrine disrupting chemical (EDC) that could mimic or inhibit the actions of endogenous estrogens. Divergent, tissue-specific (ovary vs. placenta) effects of Cd(2+) also cannot be ruled out. Therefore, in consideration of the data currently available and in light of the potentially serious consequences of environmental Cd(2+) exposure to human reproduction, we propose that priority should be given to studies dedicated to further elucidating the mechanisms involved.