Effect of Early Exposure on Reproductive Outcomes
Exposures of children to environmental toxicants during critical stages of reproductive system development can have serious and long-lasting effects. Reproductive system development takes place both during pre- and postnatal life and is under extensive hormonal control. Therefore, the opportunities for disruption of normal processes of structural and functional development of this system, particularly from endocrine-disrupting chemicals, are extensive. There is clinical and epidemiological evidence that early-life exposures can result in such adverse outcomes as alterations in the timing of puberty, polycyclic ovary syndrome, premature ovarian failure, testicular dysgenesis syndrome, congenital defects and cancers of the pelvic reproductive organs, and breast cancer. Evidence from laboratory animal studies indicates the probability of an even broader array of adverse effects on human reproductive health from early-life-stage exposures to environmental toxicants. Included in this list are altered cyclicity and fecundability, disruptions of uterine development, endometriosis, uterine fibroid tumors, disorders of implantation, alterations in breast development, decreased duration of lactation, and incidence of prostate cancer. The assessment of reproductive risk from exposures to children includes the careful conduct and consideration of epidemiological data, the use of standardized animal testing paradigms, and the judicious application of primary research efforts, which are all complementary and important aspects of the process.