A review of the developmental and reproductive toxicity of styrene

The reproductive and developmental toxicity of styrene has been studied in animals and humans. The animal studies on styrene have diverse study design s and conclusions. Developmental or reproductive toxicity studies have been conducted in rats, mice, rabbits, and hamsters, In most cases, high doses are required to elicit effects, and the effects are not unique to reproduct ion or development. In a number of the reports, either the experimental des igns are limited or the descriptions of the designs and the endpoints measu red are insufficient to draw conclusions about the toxicity of styrene, The more complete and better-reported studies show that styrene does not cause developmental toxicity at dose levels that are not maternally toxic. Some neurochemical or neurobehavioral effects have been reported at high exposur es. Styrene does not affect fertility or reproductive function. Considerabl e animal toxicity data on styrene support the conclusion that styrene is ne ither an endocrine-active substance nor an endocrine disrupter. Human studi es often suffer fr-om either inadequate exposure data or exposure to a wide variety of materials, so that attribution of effects to styrene exposure i s impossible. Furthermore, investigators often have failed to account for o ther exposures in the workplace or for other potentially confounding factor s in their studies. Menstrual cycle irregularities and congenital abnormali ties were initially reported; however, the better and more recent reports d o not show that styrene causes developmental or reproductive effects in hum ans. Human studies also support the conclusion that styrene is not an endoc rine disrupter, Although some study authors have concluded that styrene is either a human or an animal reproductive or developmental toxicant, careful review demonstrates that such conclusions are not justified. (C) 2000 Acad emic Press.