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

Maribel Casas (1, 2, 3) , Sylvaine Cordier (4, 5) , David Martínez (1, 2, 3) , Henrique Barros (6, 7) , Jens Peter Bonde (8) , Alex Burdorf (9) , Nathalie Costet (5, 4) , Ana Cristina dos Santos (7, 6) , Asta Danileviciute (10) , Merete Eggesbø (11) , Mariana Fernandez (12, 2) , Joelle Fevotte (13) , Ana M García (14, 2) , Regina Gražuleviciene (10) , Eva Hallner (15, 16) , Wojciech Hanke (17) , Manolis Kogevinas (18, 1, 2, 3) , Inger Kull (19, 20, 15) , Pernille Stemann Larsen (21) , Vasiliki Melaki (22) , Christine Monfort (5, 4) , Karl-Christian Nordby (23) , Anne-Marie Nybo Andersen (21) , Evridiki Patelarou (24, 25) , Kinga Polanska (17) , Lorenzo Richiardi (26) , Loreto Santa Marina (27, 2, 28) , Claudia Snijder (9) , Adonina Tardón (29, 2) , Manon van Eijsden (30) , Tanja G M Vrijkotte (31) , Daniela Zugna (26) , Mark Nieuwenhuijsen (1, 2, 3) , Martine Vrijheid (1, 2, 3)

1 CREAL - Center for Research in Environmental Epidemiology
2 CIBER de Epidemiología y Salud Pública (CIBERESP)
3 UPF - Universitat Pompeu Fabra [Barcelona]
4 UR1 - Université de Rennes 1
5 Irset - Institut de recherche en santé, environnement et travail
6 Universidade do Porto = University of Porto
7 University of Porto Medical School
8 Bispebjerg Hospital
9 Erasmus MC - Erasmus University Medical Center [Rotterdam]
10 VDU - Vytautas Magnus University - Vytauto Didziojo Universitetas
11 Division of Epidemiology
12 UGR - Universidad de Granada = University of Granada
13 UMRESTTE UMR T9405 - Unité Mixte de Recherche Epidémiologique et de Surveillance Transport Travail Environnement
14 University of Valencia
15 IMM - The Institute of Environmental Medicine [Stockholm]
16 Stockholm County Council
17 Department of Environmental Epidemiology
18 National School of Public Health
19 Sachs' Children's Hospital
20 Department of Clinical Science and Education
21 Department of Public Health [Copenhagen]
22 University Hospital of Heraklion
23 NIOH
24 Department of Social Medicine
25 Florence Nightingale School of Nursing and Midwifery
26 Cancer Epidemiology Unit
27 BIODonostia Research Institute
28 Public Health Department
29 University of Oviedo
30 Department of Epidemiology, Documentation and Health Promotion
31 Academic Medical Centre, Department of Public Health

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.

Keywords: birth weight; occupation; cohort studies; meta-analysis; Europe; length of gestation

Domains: Life Sciences [q-bio]; Life Sciences [q-bio]; Human health and pathology; Gynecology and obstetrics

Maribel Casas, Sylvaine Cordier, David Martínez, Henrique Barros, Jens Peter Bonde, et al.. Maternal occupation during pregnancy, birth weight, and length of gestation: combined analysis of 13 European birth cohorts.. Scandinavian Journal of Work, Environment and Health, 2015, 41 (4), pp.384-96. ⟨10.5271/sjweh.3500⟩. ⟨hal-01151621⟩