Morning After Pill Not Effective for Overweight Women

As the popular Plan B emergency contraception pill comes under increasing scrutiny, CU experts say a better product is available that many women don’t know about.

Denver (Dec. 10, 2013) — News out of Europe that emergency birth control pills identical to Plan B One-Step are not as effective for overweight women—and are not effective at all for obese women—reinforces what University of Colorado Family Planning doctors have been saying for some time: there’s a better option than Plan B and more women should be using it.

A newer, FDA-approved medication called ulipristal acetate (brand name is ella) is more effective than levonorgestrel (brand name is Plan B One-Step) when used after unprotected sex, and more effective for longer. In overweight and obese women, the difference is even greater. Yet many women don’t know about ulipristal acetate—in fact, many doctors don’t know about it.

“When used within 72 hours of intercourse it is estimated that levonorgestrel prevents around 50 percent of expected pregnancies but ulipristal acetate prevents two-thirds of expected pregnancies,” says Dr. Stephanie Teal, head of CU’s Family Planning division and a top researcher on birth control. “Levonorgestrel is most effective when taken within 72 hours of unprotected sexual intercourse but ulipristal acetate stays highly effective over five days. It works longer and better than levonorgestrel.”

CU Family Planning has been advising patients who are interested in emergency contraception (often called morning after pills) that they should get a prescription for ulipristal acetate when they have their annual exam. Similarly to a man having a condom available, if a woman needs the emergency contraception she can easily get her prescription filled and use the pill.

The makers of the French morning after pill Norlevo, which has the same active ingredient as the U.S. product Plan B One-Step, will soon change its label to warn that the drug begins to lose effectiveness in women who weigh more than 165 pounds and that it is ineffective for women who weigh more than 176 pounds.

Data from the U.S. Centers for Disease Control show that the weight of the average American woman over 20 years old is 166 pounds. U.S. makers of Plan B One-Step have not commented on the European label changes.

CU Family Planning physicians hope that the news about levonorgestrel’s lack of effectiveness for overweight women will not prevent overweight women from using emergency contraception when they need it. It’s now even more important for these women to know that they have an alternative in ulipristal acetate.

More American women are using emergency contraception. In 2002 only 4.2 percent of sexually experienced women had used an emergency contraceptive. A recent CDC report shows that figure to be at 11 percent, and among women who have never married usage of an emergency contraceptive climbs to 19 percent.

Ulipristal acetate costs about $40 a pill, which is comparable to levonorgestrel. In July the FDA declared that only the brand name Plan B One-Step emergency contraceptive could be sold over-the-counter to women under 17. Ulipristal acetate requires a prescription.

Ulipristal acetate is a selective progesterone receptive modulator and it works by preventing ovulation. Teal points out that the copper IUD (brand name is ParaGard) prevents over 95 percent of expected pregnancies when used after unprotected sex, but its cost and the need for a doctor to put it in place makes it less popular as an emergency contraceptive.

About University of Colorado OB-GYN & Family Planning

University of Colorado OB-GYN & Family Planning is one of the most diversified OB-GYN practices in the Denver area. Notable services at our women’s health clinics include university hospital care with a private practice model, women’s health research & studies, contraception, pregnancy care, infertility treatment, VBAC (vaginal birth after cesarean), & menopause treatment.