We evaluated the risk of first-trimester exposures among nurses and the risk of preterm birth among participants of the Nurses’ Health Study II.
Log binomial regression was used to estimate the relative risk (RR) for preterm birth in relation to occupational risk factors, adjusting for age, parity, work schedule, physical factors, and exposures to chemicals and x-rays.
Part-time work (<= 20 hours a week) was associated with a lower risk for preterm birth [RR=0.7, 95% confidence interval (CI) = 0.6–0.9]. Self-reported exposure to sterilizing agents was associated with an increased risk (RR=1.9, 95% CI = 1.1–3.4). Other exposures, including shift work, physical factors, anesthetic gases, antineoplastic drugs, antiviral drugs, and x-ray radiation were not associated with risk of preterm birth.
These data suggest that sterilizing agents may be related to preterm birth, while physically demanding work and work schedule are not strong predictors.