ResearchObstetricsOccupational factors and risk of preterm birth in nurses
Section snippets
Study population
The Nurses' Health Study II is a national cohort study of 116,608 US female nurses aged 25-42 years at enrollment, established in 1989.7
Follow-up questionnaires are mailed every 2 years. On the 2001 biennial questionnaire, participants were asked whether they: (1) had a pregnancy since 1993; (2) worked as a nurse during the most recent of these pregnancies; and (3) would be willing to participate. An occupational supplement was mailed to women who answered yes to all 3 questions to assess
Results
Among 6977 pregnancies ending in singleton live births during which the mother reported working as a nurse in the first trimester, 588 (8%) delivered before the 37th week from LMP. Of those who reported preterm birth, 524 (89%) delivered between 32 and 36 weeks from LMP, 47 (8%) between 28 and 31 weeks, 15 (3%) between 24 and 27 weeks, and 2 (0.3%) between 20-23 weeks. Delivery was medically indicated in 40% of the study pregnancies. The prevalence of preterm birth was 9% for spontaneous births
Comment
In this large cohort of nurses, women who worked part time had a lower risk of delivering preterm, although there was not a clear dose-response relationship with overtime hours. Nurses who worked night shift had a 3-fold risk of delivering early preterm (< 32 weeks) but not with later preterm (32-36 weeks). The risk of preterm birth was moderately associated with reported exposure to sterilizing agents; however, because there were few exposed women, this finding should be interpreted
Acknowledgment
The authors gratefully acknowledge the contributions of Walter Willett, Lynne Pinkerton, James Boiano, and Julie Tackett.
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Cited by (0)
Cite this article as: Lawson CC, Whelan EA, Hibert EN, et al. Occupational factors and risk of preterm birth in nurses. Am J Obstet Gynecol 2009;200;51.e1-51.e8.
This study was supported in part by contract 200-2001-08007 from the Centers for Disease Control and Prevention and the National Institute for Occupational Safety and Health.
The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.