Occupational exposures and adverse pregnancy outcomes among nurses: a systematic review and meta-analysis.

BACKGROUND: The nursing profession has been associated with several adverse pregnancy outcomes. However, the associations between occupational exposures and adverse pregnancy outcomes among this group have not been systematically examined. This review collates all epidemiological evidence to examine the strength of associations and consistency among eligible studies. METHODS: A computer search of EMBASE and PubMed from 1966 through August 2009 was performed, followed by a search of reference lists of relevant studies and narrative reviews RESULTS: Fourteen studies explored the relation between anesthetic gases and spontaneous abortion, 8 the relation between anesthetic gases and congenital malformations, 7 the relation between chemotherapy agents and congenital malformations, and 4 the relation between shift work and spontaneous abortion. In the random-effects models the summary odds ratio (OR) was moderately elevated for all the relations: OR = 1.27, 95% confidence interval (CI) 0.99-1.63 for anesthetic gases and spontaneous abortion. The summary OR was between 1.05 and 1.09 in high-quality studies, registry-based studies, and cohort studies: OR = 1.33, 95% CI 1.09-1.68 for anesthetic gases and congenital malformation. The summary OR was between 0.97 and 1.22 for high-quality studies, registry-based studies, and cohort studies: OR = 1.35; 95% CI 0.91-2.01 for chemotherapy agent and spontaneous abortion. The summary OR was between 1.34 and 1.69 for high-quality studies, registry-based studies, and cohort studies: OR = 1.44, 95% CI 1.06-1.95 for shift work and spontaneous abortion. CONCLUSIONS: Nurses were found to be at increased risk of adverse pregnancy outcomes, but the strength of association was weaker in the well-designed studies. The significance of the findings is limited by the number and heterogeneity of the studies.