Taking a low-dose oral contraceptive pill can reduce painful periods and non-menstrual pain associated with endometriosis, research shows.

“The present study clearly demonstrated for the first time that oral contraceptive pills could be used to effectively and safely treat pain associated with endometriosis,” the study team reports in a paper published this month in the medical journal Fertility and Sterility.

Endometriosis is a painful condition that affects women during their reproductive years. It occurs when tissue that normally lines the uterus grows at other sites within the abdomen, such as the ovaries.

Dr. Tasuka Harada, from Tottori University School of Medicine in Yonago, Japan, and colleagues assessed the outcomes of 100 women with painful periods due to endometriosis who were randomized to receive a low-dose oral contraceptive pill or placebo.

The oral contraceptive was taken for 21 days plus 7 days of placebo, while the control group took identical placebo pills for 28 days. Usual pain medications were allowed. The women were treated for four cycles.

Both groups showed significant improvements in pain-related to their period, Harada and colleagues report. Throughout the treatment period, however, menstrual pain was significantly milder in women on the oral contraceptive. The women on the pill also reported less non-menstrual pain.

Treatment with oral contraceptive was also associated with a significant reduction in the volume of endometrial tissue occurring outside the uterus, an effect not seen with placebo use, the researchers note.

The oral contraceptive pill was generally well tolerated and not associated with any serious side effects.

SOURCE: Fertility and Sterility, November 2008.