Ulipristal acetate reduces breakthrough bleeding in women with etonogestrel implants, according to new findings.
After 30 days, patients treated with ulipristal were more satisfied with their bleeding profiles than were those given placebo, reported Rachel E. Zigler, MD, of the department of obstetrics and gynecology at Washington University in St. Louis and her colleagues.
About half of women experience unscheduled bleeding within the first 6 months of etonogestrel implantation, causing many to discontinue treatment. The etiology of this phenomenon is poorly understood.
“One leading theory is that sustained exposure to a progestin can lead to endometrial angiogenesis disruption, resulting in the development of a dense venous network that is fragile and prone to bleeding,” the researchers wrote in Obstetrics & Gynecology.
Ulipristal acetate is a selective progesterone receptor modulator approved for emergency contraception in the United States. Outside the United States, it is used to treat abnormal uterine bleeding in cases of uterine leiomyoma. Ulipristal acts directly upon myometrial and endometrial tissue and “may also displace local progestin within the uterus to counteract bleeding secondary to … a dense, fragile venous network.”
The double-blind, placebo-controlled study included 65 women aged 18-45 years with etonogestrel implants. Eligibility required that implants be in place for more than 90 days and less than 3 years and that participants experienced more than one bleeding episode over a 24-day time frame.
Patients received either 15 mg ulipristal (n = 32) or placebo (n = 33) daily for 7 days. From the first day of treatment until 30 days, patients self-reported bleeding events. Weekly phone questionnaires also were conducted to determine satisfaction with medication and side effects.