NEW YORK (Reuters Health) – A low-dose oral contraceptive is effective in relieving primary dysmenorrhea, according to the results of a randomized controlled trial conducted in Japan and reported in Fertility and Sterility online March 21.
Painful menstrual cramps are severe enough in up to 15% of women who experience them to limit their ability to work, the investigators note. While oral contraceptives have long been used to alleviate dysmenorrhea, few clinical trials have been conducted.
Dr. Tasuku Harada, with the Tottori University School of Medicine, and colleagues previously demonstrated that IKH-01, an OC containing 0.035 mg ethinyl estradiol and 1 mg norethisterone, was effective for endometriosis-associated dysmenorrhea. In the current study, they report results in primary dysmenorrhea.
The investigators randomized 115 women to IKH-01 or placebo for four menstrual cycles. Use of analgesic agents was allowed.
The total dysmenorrhea score dropped from 3.8 at baseline to 1.2 at the end of treatment in the IKH-01 group; in the placebo group, the baseline score of 3.6 dropped to 2.2. The difference in score change between the two groups was significant at a p value of <0.001.
Similarly, scores on a visual analog scale dropped from 57.2 to 21.2 in the active treatment group and from 60.0 to 39.2 in the placebo group (p=0.001), according to the report.
The incidence of irregular bleeding, nausea and other adverse events was higher in the IKH-01 group than the placebo group, but it decreased over time in the OC group, the authors found.