Effects of styrene on the reproductive health of women: a review.

Styrene has been shown to cross the placenta. Studies in animals suggest that styrene and styrene oxide have embryotoxic or fetotoxic effects early in pregnancy, but there is no evidence with regard to teratogenicity. This paper is a review of epidemiological investigations on the effects of occupational exposure to styrene on the reproductive health of women. The results of these studies are contradictory. Some early reports suggested that exposure to styrene induces menstrual disturbances, spontaneous abortions and congenital malformations. In more recent studies, no risk was observed among workers exposed to styrene in the reinforced-plastics industry. An excess of spontaneous abortions was, however, indicated by one investigation in women whose work included the processing of polystyrene. Two studies also suggested associations between exposure to styrene and low birth weight and reduced fertility. Although some epidemiological studies suggest that exposure to styrene involves reproductive hazards, the validity of most of these studies is weakened by methodological shortcomings. The available evidence cannot be used to draw any firm conclusions.