ISEE-0355 Objective: The overall all aim of this meta-analysis was to synthesize the evidence of the relation between exposure to various occupational hazards (anaesthetic gases, strenuous working conditions and inconvenient work schedule, chemotherapy agents, and ethylene oxide) and the risk of adverse pregnancy outcomes among nurses, and further explore the reasons for heterogeneity among studies included in the analysis. Methods: The authors performed a computer search of EMBASE and PUBMED from 1966 to January 2009 and also searched reference lists of reviews and eligible articles for all epidemiologic studies that have explored the relation between occupational exposures and adverse pregnancy outcomes among nurses. Results: Ten studies explored the relation between anaesthetic gases and spontaneous abortion. Five studies examined the relation between chemotherapy agents and spontaneous abortion, 7 studies explored the relation between anaesthetic gases and general congenital malformation. And 3 and 4 studies examined the relation between preterm delivery and anaesthetic gases and strenuous working conditions respectively. Increased risk of spontaneous abortion (Odds ratio (OR) = 1.73, 95% confidence interval (CI): 1.60, 1.88) and congenital malformation (OR = 1.45, 95% CI: 1.06, 1.49) was associated with anaesthetic gases. But the relation between chemotherapy agents and spontaneous abortion was weak (OR = 1.28, 95% CI: 0.84, 1.94). Inconsistent and suggestive evidence of excesses was observed for the relation between preterm delivery and anaesthetic gases and strenuous working conditions. Conclusions: There was evidence of association among occupational exposures and adverse pregnancy outcomes. Nevertheless, the findings were complicated by the limited number of studies and inexplicable heterogeneity.