Occupational factors and risk of preterm birth in nurses

• Published in: American journal of obstetrics and gynecology 2009-01, Vol.200 (1), p.51.e1-51.e8
• Main Authors: Lawson, Christina C., PhD, Whelan, Elizabeth A., PhD, Hibert, Eileen N., MA, Grajewski, Barbara, PhD, Spiegelman, Donna, ScD, Rich-Edwards, Janet W., ScD
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Cohort Studies; Diseases of mother, fetus and pregnancy; Female; Gynecology. Andrology. Obstetrics; Humans; Medical sciences; Nurses; Obstetrics and Gynecology; Occupational Diseases - etiology; occupational exposure; Occupational Exposure - adverse effects; Odds Ratio; Pregnancy; Pregnancy Trimester, First; Pregnancy. Fetus. Placenta; Premature Birth - etiology; preterm birth; Risk Factors; work schedule tolerance
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/j.ajog.2008.08.006

Objective We evaluated first-trimester exposures and the risk of preterm birth in the most recent pregnancy of participants of the Nurses' Health Study II. Study Design Log binomial regression was used to estimate the relative risk (RR) for preterm birth in relation to occupational risk factors, such as work schedule, physical factors, and exposures to chemicals and x-rays, adjusted for age and parity. Results Part-time work (≤ 20 hours a week) was associated with a lower risk of preterm birth [RR, 0.7; 95% confidence interval [CI], 0.6-0.9]. Working nights was associated only with early preterm birth (< 32 weeks of gestation) (RR, 3.0; 95% CI, 1.4-6.2). Although based on only 11 exposed preterm cases, self-reported exposure to sterilizing agents was associated with an increased risk (RR, 1.9; 95% CI, 1.1-3.4). Conclusion These data suggest that night work may be related to early but not late preterm birth, whereas physically demanding work did not strongly predict risk.