New morning-after pill effective up to 5 days after

January 29, 2010 by Shawn Douglas
Filed under: News

A new morning-after pill has been shown to be effective at stopping a woman from getting pregnant up to 5 days after unprotected sex.

Research out of the University of Edinburgh and NHS Lothian in Scotland compared the effectiveness of commonly available morning-after pill levonorgestrel with a new form, ulipristal acetate.

The research, published in the medical journal The Lancet, found that the newly available ulipristal acetate more than halved the rate of pregnancy compared to levonorgestrel and held its effectiveness up to five days after having unprotected sex.

The British Pregnancy Advisory Service welcomed the research, calling the results of the new drug “exciting news.”

Ann Furedi, the service’s chief executive, told the BBC that ulipristal “offers a longer time window for use than the traditional, emergency contraception pill.”

“Different hormones are involved to the ones traditionally used in contraception, so it may be that these will prove to have other contraceptive uses in the future,” she added.

Researchers conducted their own research, combining the results with another recent study. In all, 1,694 women who visited clinics in the Republic of Ireland, the U.K. and the U.S. to obtain emergency contraception participated in the research.

All the women arrived within five days of having unprotected sex. The researchers randomly assigned one of the two pills. Among the women, 15 became pregnant after taking the new ulipristal acetate while 22 became pregnant using levonorgestrel.

From the group, 203 of the women asked for emergency contraception between three and five days after unprotected sex. In that group, three women became pregnant, all of whom had taken levonorgestrel.

Professor Anna Glasier, who headed the research study, noted that there was only a six percent rate of pregnancy expected out of the group, making it difficult to pinpoint who exactly required the contraception the most. “Arguably, over 90 percent of participants did not need to use emergency contraception,” said Glasier. “The difficulty, however, is in identifying this small population of women.”

There are concerns, however, about the availability of the new contraceptive. While ulipristal was licensed for sale in Europe last May, the pill is not yet available over the counter, in part because it doesn’t have the established record of safety that levonorgestrel has. In addition, the new pill costs up to three times more than levonorgestrel. This has led to some concern that the women who need it the most won’t be able to access it.