A study has linked two pesticides with an increased risk of endometriosis, a condition affecting up to 10 percent of reproductive-age women.

Specifically, researchers observed that women with higher exposures to two such pesticides, beta-hexachlorocyclohexane and mirex, had a 30- to 70-percent increase in endometriosis risk.

Endometriosis is a noncancerous condition that occurs when the tissue that lines the inside of the uterus, or womb, grows outside of the organ and attaches to other structures or organs.

The condition most often affects the ovaries, fallopian tubes and lining of the pelvic cavity. The most common symptoms include chronic pelvic pain, painful menstrual periods and infertility.

Lead and corresponding author Kristen Upson , Ph.D., who was a predoctoral research fellow in epidemiology at Fred Hutch and the University of Washington when the study was conducted, said that for many women, the symptoms of endometriosis can be chronic and debilitating, negatively affecting health-related quality of life, personal relationships and work productivity.

She said that since endometriosis is an estrogen-driven condition, we were interested in investigating the role of environmental chemicals that have estrogenic properties, like organochlorine pesticides, on the risk of the disease.

The findings have been published online in journal Environmental Health.