Harvard Women's Health Watch

An emergency contraceptive pill helps treat fibroids

Every year, hundreds of thousands of women in the United States are treated for fibroids — noncancerous growths in the uterine wall. Fibroids don't always cause problems, but when they do, the most common complaint is heavy menstrual bleeding, often accompanied by iron-deficiency anemia. Fibroids can also cause pelvic pain and pressure, and they're associated with miscarriage and infertility. Treatments for fibroids consist mostly of surgery — for example, myomectomy or hysterectomy — and minimally invasive procedures such as uterine artery embolization. Medications called gonadotropin-releasing hormone agonists — in particular, leuprolide (Lupron), given by injection — can help shrink fibroids. However, their use is limited by side effects such as bone loss, hot flashes, and depression. Now, researchers have found that an oral drug with fewer side effects is highly effective in shrinking fibroids and reducing bleeding. This drug, ulipristal acetate, is currently marketed as Ella for emergency contraception. Findings were published in the Feb. 2, 2012, issue of The New England Journal of Medicine.

The study. Belgian researchers tested ulipristal in two industry-funded trials at research centers in Europe. In the first trial, 242 women ages 18 to 50 with bothersome fibroids and bleeding were assigned at random to one of two doses of ulipristal (5 mg or 10 mg) or a placebo for 13 weeks before planned surgery. After 13 weeks, uterine bleeding was under control in 91% of the women receiving the 5-mg dose and 92% of those taking the 10-mg dose, compared with 19% of those taking a placebo. Fibroid size was also reduced — by 21% in the 5-mg group and 12% in the 10-mg group, while it increased by 3% in the placebo group. In the second trial, 307 women with excessive bleeding caused by fibroids were assigned to three months of ulipristal (5 mg or 10 mg) or monthly leuprolide injections before surgery. After 13 weeks, bleeding was under control in 90% of the women receiving 5 mg of ulipristal, 98% of those receiving 10 mg of ulipristal, and 89% of those receiving leuprolide. Women in all three groups also experienced similar reductions in fibroid size and pain. But ulipristal (at either dose) suppressed bleeding more quickly — within a week or less, compared with 21 days for leuprolide. And ulipristal had fewer side effects — especially hot flashes — than leuprolide, which has a greater effect on estrogen levels. A six-month follow-up showed that for women who chose not to undergo surgery, ulipristal was better than leuprolide at maintaining the reduced fibroid size.

Limitations and implications. Ulipristal is a selective progesterone receptor modulator (SPRM), which works by blocking progesterone. Because progesterone protects the endometrium against estrogen-induced excessive cell growth, there's some concern that blocking it can spur precancerous changes. In these trials, endometrial biopsies performed at 13 weeks and again at 38 weeks (in women who did not undergo hysterectomy) showed no precancerous or cancerous changes. However, the trials were relatively short and focused on treating fibroids before surgery. More research is needed to determine whether ulipristal is safe and effective for the long-term treatment of fibroids.

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