New research shows that the emergency contraception drug ulipristal acetate (UA) prevents more pregnancies than a widely-used alternative, levonorgestrel. Furthermore, UA has recently been licensed for use up to five days after unprotected intercourse, compared with just three days for levonorgestrel. Thus women and health-care providers now have an alternative choice for emergency contraception. The findings are published in an Article Online First (www.thelancet.com) and in an upcoming edition of The Lancet—written by Dr Anna Glasier, NHS Lothian, Edinburgh, UK and colleagues.
The authors of this study performed their own trial, and also combined their results with a previous study (meta-analysis). Their own trial took place in the UK, Ireland, and the USA. Women with regular menstrual cycles who presented to a participating family planning clinic requesting emergency contraception within 5 days of unprotected sexual intercourse were eligible for enrolment in this randomised trial. A total of 2221 women were randomly assigned to receive a single dose of 30 mg UA (n=1104) or 1•5 mg levonorgestrel (n=1117) orally. Participants did not know which treatment they were receiving but investigators did. Follow-up was done 5 days after expected onset of the woman's next expected period. The primary endpoint was pregnancy rate in women who received emergency contraception within 72 h of unprotected sexual intercourse.
The final analysis excluded women lost to follow-up, those aged over 35 years, women with unknown follow-up pregnancy status, and those who had re-enrolled in the study—and consisted of 1694 women, of whom 844 in the UA group and 852 in the levonorgestrel group received emergency contraception within 72 h of sexual intercourse. There were 15 pregnancies in the UA group (1•8%) and 22 in the levonorgestrel group (2•6%). In 203 women who received emergency contraception between three and five days after sexual intercourse, there were three pregnancies, all in the levonorgestrel group. The most frequent adverse event was headache (UA, 213 events [19•3%] in 1104 women; levonorgestrel, 211 events [18•9%] in 1117 women). Two serious adverse events were judged possibly related to use of emergency contraception; a case of dizziness in the UA group and a molar pregnancy in the levonorgestrel group. In the meta-analysis (0-72 hours), there were 22 (1•4%) pregnancies in the UA group and 35 (2•2%) in the levonorgestrel group.
Combination of data from the two studies allowed analysis of a sample sufficiently large to show that UA almost halved the risk of becoming pregnant compared to levonorgestrel in women who received emergency contraception within 120 h (five days) after sexual intercourse. If emergency contraception was used within 24 h of unprotected sexual intercourse (when a third of participants in the study presented for emergency contraception), the risk of pregnancy was reduced by almost two-thirds compared to levonorgestrel.
The authors discuss that the UA has been approved by the European Medicines Agency (May 2009) as a safe and effective method of emergency contraception for use up to five days after unprotected sexual intercourse—and is currently being launched throughout Europe.
They add: "The estimated expected pregnancy rate in our trial was less than 6%, so arguably over 90% of participants did not need to use emergency contraception. The difficulty, however, is in identifying this small population of women."
The authors point out that, since levonorgestrel has been used by many millions of women in varying doses, it can be made available without prescription. However, although UA could be made available through pharmacies and via nurses, it cannot be made as easily accessible as levonorgestrel until more safety data become available. They conclude: "Despite the issues around health-care service delivery, ulipristal acetate provides women and health-care providers with an alternative choice for emergency contraception that can be used up to 5 days after unprotected sexual intercourse."
Dr Anna Glasier, NHS Lothian, Edinburgh, UK. T) +44 (0) 131 343 0912 / +44 (0) 131 343 0900 E) Anna.Glasier@nhslothian.scot.nhs.uk
For full Article see: http://press.thelancet.com/ua.pdf
Note to editors: An accompanying Comment is not available at this time, it will be available when the Article is published in a future issue of The Lancet.
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The Lancet