New Emergency Contraception Drug Stirs Old Arguments

By Rachel Walden — February 9, 2010

A recent ABC news piece and two new journal articles (in The Lancet and Obstetrics and Gynecology) have drawn attention to an emergency contraception drug that is not currently available in the U.S. but apparently has been submitted to the FDA for review.

Emergency contraception pills (EC) currently available in the U.S.  are intended to be taken within 72 hours (3 days) of unprotected intercourse or contraceptive failure.  The drug new drug, ellaOne (ulipristal acetate), can be taken within 120 hours (5 days), providing a longer period in which to prevent pregnancy. [It’s worth noting here that women have long been advised that existing EC options can also be taken up to 5 days after intercourse, although that’s not the “official” approved recommendation on the drug inserts].

Anti-choice groups such as the American Association of Pro-Life Obstetricians and Gynecologists argue that the pill could cause abortions and be an OTC abortion pill in the U.S., using a definition of “pregnancy” that includes a non-implanted fertilized egg, a definition that is generally not medically or scientifically accepted. These arguments were also presented during debate over the approval of Plan B.

The Lancet study compared ulipristal acetate (30 mg) with levonorgestrel (1.5 mg, the drug in Plan B) among adult women in the US and UK seeking emergency contraception within 120 hours of unprotected intercourse.

The women were followed for pregnancy outcomes, and both drugs significantly reduced the expected pregnancy rate, with the outcomes demonstrating that ulipristal was not inferior to levonorgestrel at preventing pregnancy.

The researchers also looked at rates of pregnancy among those 203 women who received one of the drugs 72-120 hours after unprotected intercourse. They found reduced rates of pregnancy: 0 in the ulipristal group, and 3 pregnancies in the levonorgestrel group, a statistically greater reduction in the ulipristal group (although a couple of changes either way might make a big difference in this result).

The second study, in Obstetrics and Gynecology, also looked at efficacy of ulipristal acetate over various time periods, up to 120 hours, and seemed to demonstrate continuing efficacy beyond 72 hours.

Both studies were funded by the company that owns ulipristal acetate.

A librarian note: searching PubMed for ulipristal acetate only returns a few citations; a search for “CDB 2914″[Substance Name] OR “CDB-2914” OR “ulipristal acetate” OR “ellaone” is more comprehensive.

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