The effects of work-related maternal risk factors on time to pregnancy, preterm birth and birth weight: the Generation R Study
- 1The Generation R Study Group, Erasmus MC, Rotterdam, The Netherlands
- 2Department of Public Health, Erasmus MC, Rotterdam, The Netherlands
- 3Coronel Institute, Netherlands Center for Occupational Diseases, Academic Medical Center Amsterdam, Amsterdam, The Netherlands
- 4Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands
- 5Department of Pediatrics, Erasmus MC, Rotterdam, The Netherlands
- 6Department of Obstetrics and Gynecology, Erasmus MC, Rotterdam, The Netherlands
- Correspondence to Alex Burdorf, Department of Public Health, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands;
- Accepted 9 June 2010
- Published Online First 20 December 2010
Objective To investigate the influence of maternal working conditions on fertility and pregnancy outcomes.
Methods 8880 women were enrolled in a large prospective birth cohort during early (76%), mid (21%) or late pregnancy (3%) (61% participation). Complete questionnaire information was available for 6302 women (71% response). Outcomes were prolonged time to pregnancy (TTP) (>6 months), preterm birth (<37 weeks) and decreased birth weight (<3000 g). Self-reported exposure to chemical agents was based on a limited list of chemicals. Physical load questions concerned manual materials handling, prolonged sitting and long periods of standing. A job-exposure matrix (JEM) linked reported job title to workplace chemical exposure within jobs according to expert judgement. Associations between maternal occupational exposure and fertility and pregnancy outcomes, adjusted for age, education, minority, parity, smoking and alcohol use, were studied using logistic regression analysis.
Results Women in jobs with regular handling of loads ≥5 kg had better fertility and pregnancy outcomes. No self-reported exposure to chemicals was associated with any outcomes and self-assessments had very low reliability compared with JEM-based assessments. JEM-based maternal occupational exposure to phthalates was associated with prolonged TTP (OR 2.16, 95% CI 1.02 to 4.57) and exposure to pesticides was associated with decreased birth weight (OR 2.42, 95% CI 1.10 to 5.34). The population attributable fractions were small at 0.7% for phthalates and 0.7% for pesticides.
Conclusion This birth cohort study presents evidence of health-based selection into the workforce and adverse effects of maternal occupational exposure to phthalates and pesticides on fertility and pregnancy outcomes.
The Generation R Study is conducted by Erasmus MC, University Medical Center Rotterdam in close collaboration with: Erasmus University Rotterdam, School of Law and Faculty of Social Sciences; the Municipal Health Service Rotterdam area, Rotterdam; the Rotterdam Homecare Foundation, Rotterdam; and the Stichting Trombosedienst and Artsenlaboratorium Rijnmond (STAR), Rotterdam.
Funding The first phase of the Generation R Study is made possible by financial support from Erasmus MC, University Medical Centre Rotterdam, Erasmus University Rotterdam and the Netherlands Organization for Health Research and Development (ZonMw). The present study was commissioned by the Netherlands Center for Occupational Diseases (NCVB) in Amsterdam, supported by a grant from the Ministry of Social Affairs and Employment of the Netherlands.
Competing interests None.
Ethics approval This study was conducted with the approval of Erasmus MC, Rotterdam.
Provenance and peer review Not commissioned; externally peer reviewed.