Scandinavian Journal of Work, Environment & Health (Jul 2015)

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

  • Maribel Casas,
  • Sylvaine Cordier,
  • David Martínez,
  • Henrique Barros,
  • Jens Peter Bonde,
  • Alex Burdorf,
  • Nathalie Costet,
  • Ana Cristina dos Santos,
  • Asta Danileviciute,
  • Merete Eggesbø,
  • Mariana F Fernandez,
  • Joelle Fevotte,
  • Ana M García,
  • Regina Gražuleviciene,
  • Eva Hallner,
  • Wojciech Hanke,
  • Manolis Kogevinas,
  • Inger Kull,
  • Pernille Stemann Larsen,
  • Vasiliki Melaki,
  • Christine Monfort,
  • Karl-Christian Nordby,
  • Anne-Marie Nybo Andersen,
  • Evridiki Patelarou,
  • Kinga Polanska,
  • Lorenzo Richiardi,
  • Loreto Santa Marina,
  • Claudia Snijder,
  • Adonina Tardón,
  • Manon van Eijsden,
  • Tanja GM Vrijkotte,
  • Daniela Zugna,
  • Mark Nieuwenhuijsen,
  • Martine Vrijheid

DOI
https://doi.org/10.5271/sjweh.3500
Journal volume & issue
Vol. 41, no. 4
pp. 384 – 396

Abstract

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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_adj 0.91, 95% CI 0.84–0.99) whereas food industry workers had an increased risk of preterm delivery (OR_adj 1.50, 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.

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