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Drug May Hold Key to Preventing 'Breakthrough Bleeding'

New study will look at the efficacy of doxycycline in stopping unscheduled menstrual bleeding in women on continuous hormonal contraception.

A new study looks to evaluate doxycycline, a common antibiotic used to treat infections and acne, as a possible treatment in preventing or stopping unexpected menstrual bleeding in women who use continual hormonal contraception. The study is based at the Women's Health Research Unit, part of the Oregon Health & Science University's Center for Women's Health.

If the study shows the drug is successful in stopping "breakthrough bleeding," more women may turn to new continuous contraception options – options that allow women to effectively stop menstrual bleeding, said study investigator Bliss Kaneshiro, M.D.,instructor in obstetrics and gynecology, OHSU School of Medicine.

To women like Portland resident Allison Knowles, 26, continuous hormonal contraception without breakthrough bleeding is an attractive option. "I don't have a 'bad' period," she said. "But I'm athletic and always working out, and I also travel a lot for work. It's not always convenient to have your period. So, being able to not have one definitely appealed to me."

As a participant in the study, Knowles is currently taking Lybrel, the first FDA approved continuous oral contraceptive. As part of the study, Knowles keeps a journal where she enters the details of any menstrual bleeding. Knowles has experienced some breakthrough bleeding, but she does not know if she has received the study medication, doxycycline, or a placebo to treat the bleeding.

Many women who drop their monthly period through continuous hormonal contraception continue to have unscheduled bleeding as their body adjusts to the contraception – as many as 62 percent experienced some unscheduled bleeding while adjusting to Lybrel, according to studies sponsored by Wyeth Pharmaceuticals, the producers of Lybrel. Breakthrough bleeding may be a deterrent to women who would otherwise opt for period-eliminating contraception.

"Not having a menstrual period is a great option for many women, especially women who are active, have painful periods or just find that having a period is a nuisance. However, one of the downsides of starting a continuous method is the unexpected bleeding that women experience in the first few months of use. This breakthrough bleeding leads many women to stop taking continuous birth control and finding a way to eliminate or decrease unexpected bleeding could lead more women to stick with this birth control method," Kaneshiro said.

Knowles, who has been in the study for about six weeks, says that if the study can find a way to eliminate breakthrough bleeding, she would definitely consider making a permanent switch to continuous hormonal contraception.

Kaneshiro said, "Taking a birth control pill that eliminates a menstrual period will not appeal to all women, but for many women, it will be an attractive contraceptive choice that fits with their lifestyle."

To enroll in the study or for more information, interested women should contact the OHSU Women's Health Research Unit hotline at 503 494-3666.

The study is supported by Wyeth Pharmaceuticals and an anonymous donor.

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The OHSU Center for Women's Health is a designated National Center of Excellence in Women's Health. The Women's Health Research Unit is a division of the Department of Obstetrics & Gynecology and an important part of the Center for Women's Health. Studies at the Women's Health Research Unit range from birth control options to treatment for the conditions associated with menopause. OBGYN board-certified physicians conduct all studies. Participants in these projects receive study drug, study-related lab tests and procedures at no cost and sometimes compensation for time and travel.

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