Working conditions and adverse pregnancy outcome: A meta-analysis

Objective: To evaluate the association between working conditions and adver se pregnancy outcomes by performing a meta-analysis of published studies. Data Sources: We searched the English-language literature in MEDLINE throug h August 1999 using the terms standing, posture, work, workload, working co nditions, shift, occupational exposure, occupational diseases, lifting, pre gnancy complications, pregnancy, small for gestational age (SGA), fetal gro wth retardation (FGR), preterm, and labor. Methods of Stimy Selection: We included observational studies evaluating th e effect of one or more of the following work-related exposures on adverse pregnancy outcome: physically demanding work, prolonged standing, long work hours, shift work, and cumulative work fatigue score. Outcomes of interest were preterm birth, hypertension or preeclampsia, and SGA. We conducted a meta-analysis based on 160,988 women in 29 studies to evalua te the association of physically demanding work, prolonged standing, long w orking hours, shift work, and cumulative work fatigue score with preterm bi rth. Also analyzed were the associations of physically demanding work with hypertension or preeclampsia and SGA infants. The data were analyzed using the Peto-modified Mantel-Haenszel method to estimate the pooled odds ratios (ORs) and 95% confidence intervals (CIs). Tabulation, Integration, and Results: Physically demanding work was signifi cantly associated with preterm birth (OR 1.22, 95% CI 1.16, 1.29), SGA (OR 1.37, 95% CI 1.30, 1.44), and hypertension or preeclampsia (OR 1.60, 95% CI 1.30, 1.96). Other occupational exposures significantly associated with pr eterm birth included prolonged standing (OR 1.26, 95% CI 1.13, 1.40), shift and night work (OR 1.24, 95% CI 1.06, 1.16), and high cumulative work fati gue score (OR 1.63, 95% CI 1.33, 1.98). We found no significant association between long work hours and preterm birth (OR 1.03, 95% CI 0.92, 1.16). Conclusion: Physically demanding work may significantly increase a woman's risk of adverse pregnancy outcome. (C) 2000 by The American College of Obst etricians and Gynecologists.