The effects of standing, lifting and noise exposure on preterm birth, growth restriction, and perinatal death in healthy low-risk working military women.

Objective: The effects of standing, lifting and noise in low-risk, healthy pregnant women are uncertain. In the past, the heterogeneity of the populations studied, the limitations of the designs of the retrospective and case control studies, and a failure of some of the larger investigations to evaluate all the potential confounding variables has hampered many studies. The purpose of this investigation was to evaluate, throughout pregnancy, the effects of standing, repetitive lifting, and noise in the workplace compared with no standing, lifting or noise exposure, on maternal and perinatal outcomes in a large prospective study of a low-risk healthy population of working women cared for by a single group of health providers.

Methods: This prospective observational study used an extensive questionnaire to collect antepartum, intrapartum, and postpartum information. Information was collected on the initial visit, each subsequent visit, and immediately after delivery. The participating women were divided into groups based on the amount of time spent standing, the amount and extent of repetitive lifting, and noise exposure in the workplace.

Results: Eight hundred and fourteen low-risk active duty women participated in this investigation over a 4-year period. Multivariate analysis with non-exposure compared with exposure reinforced the effect of standing on preterm labor (OR 1.80, 95% CI 1.05, 3.16) and preterm birth (OR 1.69, 95% CI 1.03, 2.80) and showed a trend toward an effect of noise exposure on preterm labor (OR 1.76, 95% CI 0.78, 3.39) after controlling for other exposures.

Conclusions: This investigation suggests an association of occupational standing with preterm labor and preterm birth.