Occupational Exposure to Endocrine-Disrupting Chemicals and Birth Weight and Length of Gestation: A European Meta-Analysis.

BACKGROUND: Women of reproductive age can be exposed to endocrine-disrupting chemicals (EDCs) at work, and exposure to EDCs in pregnancy may affect fetal growth. OBJECTIVES: We assessed whether maternal occupational exposure to EDCs during pregnancy as classified by application of a job exposure matrix was associated with birth weight, term low birth weight (LBW), length of gestation, and preterm delivery. METHODS: Using individual participant data from 133,957 mother-child pairs in 13 European cohorts spanning births from 1994 through 2011, we linked maternal job titles with exposure to 10 EDC groups as assessed through a job exposure matrix. For each group, we combined the two levels of exposure categories (possible and probable) and compared birth outcomes with the unexposed group (exposure unlikely). We performed meta-analyses of cohort-specific estimates. RESULTS: Eleven percent of pregnant women were classified as exposed to EDCs at work during pregnancy, based on job title. Classification of exposure to one or more EDC group was associated with an increased risk of term LBW [odds ratio (OR) = 1.25; 95% CI: 1.04, 1.49], as were most specific EDC groups; this association was consistent across cohorts. Further, the risk increased with increasing number of EDC groups (OR = 2.11; 95% CI: 1.10, 4.06 for exposure to four or more EDC groups). There were few associations (p < 0.05) with the other outcomes; women holding job titles classified as exposed to bisphenol A or brominated flame retardants were at higher risk for longer length of gestation. CONCLUSION: Results from our large population-based birth cohort design indicate that employment during pregnancy in occupations classified as possibly or probably exposed to EDCs was associated with an increased risk of term LBW. Citation: Birks L, Casas M, Garcia AM, Alexander J, Barros H, Bergström A, Bonde JP, Burdorf A, Costet N, Danileviciute A, Eggesbø M, Fernández MF, González-Galarzo MC, Grazuleviciene R, Hanke W, Jaddoe V, Kogevinas M, Kull I, Lertxundi A, Melaki V, Andersen AM, Olea N, Polanska K, Rusconi F, Santa-Marina L, Santos AC, Vrijkotte T, Zugna D, Nieuwenhuijsen M, Cordier S, Vrijheid M. 2016. Occupational exposure to endocrine-disrupting chemicals and birth weight and length of gestation: a European meta-analysis. Environ Health Perspect 124:1785-1793; http://dx.doi.org/10.1289/EHP208.

Maternal occupation during pregnancy, birth weight, and length of gestation: combined analysis of 13 European birth cohorts.

OBJECTIVES: We assessed whether maternal employment during pregnancy - overall and in selected occupational sectors - is associated with birth weight, small for gestational age (SGA), term low birth weight (LBW), length of gestation, and preterm delivery in a population-based birth cohort design. METHODS: We used data from >200 000 mother-child pairs enrolled in 13 European birth cohorts and compared employed versus non-employed women. Among employees, we defined groups of occupations representing the main sectors of employment for women where potential reproductive hazards are considered to be present. The comparison group comprised all other employed women not included in the occupational sector being assessed. We performed meta-analyses of cohort-specific estimates and explored heterogeneity. RESULTS: Employees had a lower risk of preterm delivery than non-employees [adjusted odds ratio (OR adj) 0.86, 95% confidence interval (95% CI) 0.81-0.91]. Working in most of the occupational sectors studied was not associated with adverse birth outcomes. Being employed as a nurse was associated with lower risk SGA infants (OR adj0.91, 95% CI 0.84-0.99) whereas food industry workers had an increased risk of preterm delivery (OR adj1.50, 95% CI 1.12-2.02). There was little evidence for heterogeneity between cohorts. CONCLUSIONS: This study suggests that, overall, employment during pregnancy is associated with a reduction in the risk of preterm birth and that work in certain occupations may affect pregnancy outcomes. This exploratory study provides an important platform on which to base further prospective studies focused on the potential consequences of maternal occupational exposures during pregnancy on child development.

Social capital in pregnancy and postpartum depressive symptoms: a prospective mother-child cohort study (the Rhea study).

BACKGROUND: Depression, and to a lesser extent postpartum depressive symptoms, have been associated with characteristics of the social environment and social capital. Up to the present, mostly cross-sectional studies have explored such an association without providing a clear temporal relationship between social capital and depression. OBJECTIVES: To estimate prospectively the effect of individual-level self-reported maternal social capital during pregnancy on postpartum depressive symptoms. DESIGN: Prospective mother-child cohort (Rhea study). SETTINGS: 4 prenatal clinics in Heraklion, Crete, Greece. PARTICIPANTS: All women for one year beginning in February 2007. From the 1388 participants, complete data were available for 356 women. METHODS: Women self-completed two questionnaires: The Social Capital Questionnaire at about the 24th week of gestation and the Edinburgh Postnatal Depression Scale (range 0-30) at about the 8-10th week postpartum. Maternal social capital scores were categorized into three groups: the upper 10% was the high social capital group, the middle 80% was the medium and the lowest 10% was the low social capital group that served as the reference category. Multivariable log-binomial and linear regression models were performed for: the whole available sample; for participants with a history of depression and/or prenatal EPDS≥13; for participants without any previous or current depression and prenatal EPDS score<13. Potential confounders included demographic, socio-economic, lifestyle and pregnancy characteristics that have an established or potential association with maternal social capital in pregnancy or postpartum depressive symptoms or both. RESULTS: Higher maternal social capital was associated with lower EPDS scores (highest vs lowest group: ß-coefficient=-3.95, 95% CI -7.75, -0.14). Similar effects were noted for the subscale value of life/social agency (highest vs lowest group: ß-coefficient=-5.96, 95% CI -9.52, -2.37). This association remained significant for women with and without past and/or present depression only for the subscale value of life/social agency although with a more imprecise estimate. No effect was found for participation, a structural dimension of social capital. CONCLUSIONS: Women with higher individual-level social capital in mid-pregnancy reported less depressive symptoms 6-8 weeks postpartum. Given the proposed association of perceptions of the social environment with postpartum depressive symptoms, health professionals should consider evidence-based interventions to address depression in a social framework.

Dietary patterns during pregnancy and the risk of postpartum depression: the mother-child 'Rhea' cohort in Crete, Greece.

OBJECTIVE: To identify and describe dietary patterns in a cohort of pregnant women, and investigate whether dietary patterns during pregnancy are related to postpartum depression (PPD). DESIGN: The study uses data from the prospective mother-child cohort 'Rhea' study. Pregnant women completed an FFQ in mid-pregnancy and the Edinburg Postpartum Depression Scale (EPDS) at 8-10 weeks postpartum. Dietary patterns during pregnancy ('health conscious', 'Western') were identified using principal component analysis. Associations between dietary patterns categorized in tertiles and PPD symptoms were investigated by multivariable regression models after adjusting for confounders. SETTING: Heraklion, Crete, Greece, 2007-2010. SUBJECTS: A total of 529 women, participating in the 'Rhea' cohort. RESULTS: High adherence to a 'health conscious' diet, characterized by vegetables, fruit, pulses, nuts, dairy products, fish and olive oil, was associated with lower EPDS scores (highest v. lowest tertile: ß-coefficient = -1·75, P = 0·02). Women in the second (relative risk (RR) = 0·52, 95 % CI 0·30, 0·92) or third tertile (RR = 0·51, 95 % CI 0·25, 1·05) of the 'health conscious' dietary pattern were about 50 % less likely to have high levels of PPD symptoms (EPDS ≥ 13) compared with those in the lowest tertile. CONCLUSIONS: This is the first prospective study showing that a healthy diet during pregnancy is associated with reduced risk for PPD. Additional longitudinal studies and trials are needed to confirm these findings.