Environmental Science & Technology, November 12, 2008

FEMALE FETUSES ARE SENSITIVE TO HORMONE DISRUPTERS

[Rachel's introduction: Exposure of females to hormone-disrupting compounds early in life can lead to many reproductive disorders in adulthood, including early puberty, impaired fertility, and uterine fibroids.]

By Janet Pelley

Although the association between human male reproductive health and synthetic chemicals has been explored for more than 10 years, researchers have just compiled a similar evaluation for females. The study, published online in Fertility and Sterility in October, indicates that exposure in the womb to chemicals that disrupt the endocrine system may be an important factor in painful and costly reproductive diseases that affect a majority of adult women in the U.S.

A team of 18 scientists combed through more than 300 studies on the contribution of endocrine-disrupting compounds to disorders of the ovary, uterus, breast, and pubertal timing. Experiments with rats and mice reveal that many ubiquitous chemicals such as PCBs, the herbicide atrazine, and plasticizers have detrimental effects on the female reproductive tract. Because the reproductive physiology of humans and rodents is remarkably similar, it is reasonable to predict that human female reproductive fitness can be disrupted by these compounds, according to the study.

Human epidemiology studies also support these predictions, the researchers add. For example, women who were exposed in the womb to diethylstilbestrol (DES), an estrogenic compound used before 1971 to prevent miscarriages, are more likely to have rare cervicovaginal cancers, decreased fertility, and breast cancer.

"We're increasingly finding that early life exposures are critically important for adult onset of disease," says report coauthor Sarah Janssen, a reproductive biologist at the Natural Resources Defense Council, an advocacy group. Studies on rodents have shown that exposure to the plasticizer bisphenol A (BPA) early in life disrupts the growth of breast tissue, leading to cancerous lesions in the mammary glands of adult animals. Human studies have shown that exposing normal breast tissue samples to environmentally relevant concentrations of BPA results in changes in gene expression similar to those found in aggressive breast cancer, Janssen says.

The researchers call for international coordination of research and more data on human exposures, especially data linking human fetal exposures to adult onset of disorders and improved data on the occurrence of women's reproductive health problems. They recommend making information on how to reduce exposures more accessible to the public and call for reducing contamination of air, water, and land with endocrine-disrupting compounds.

Copyright 2008 American Chemical Society