Abstract
Background
Emergency contraception (EC) is used to prevent unintended pregnancies. The current
gold standard for oral EC is levonorgestrel (LNG) administered as a single 1.5-mg
dose or in 2 doses of 0.75 mg separated by 12 hours. LNG has shown to be effective
up to 72 hours after coitus. Ulipristal acetate (UPA) is a selective progesterone
receptor modulator approved for EC use in the United States in August 2010. UPA is
administered as a one-time, 30-mg dose within 120 hours of intercourse.
Objective
The goal of this review was to provide a summary of the available literature on the
use of UPA for EC.
Methods
PubMed, Cochrane Library, ClinicalTrials.gov, International Pharmaceutical Abstracts, EBSCO, and Iowa Drug Information Service
were searched from February 2011 through September 2011 to identify relevant articles.
Search terms included ulipristal acetate, CDB-2914, VA 2914, and emergency contraception.
Results
In an open-label study, UPA was effective in preventing pregnancy in 1241 women who
presented for EC up to 120 hours (5 days) after unprotected intercourse, with an observed
pregnancy rate of 2.1% (95% CI, 1.4%–3.1%) versus 5.5% (ie, the expected pregnancy
rate without EC). The efficacy of UPA did not decrease significantly (P = 0.44) over time, with pregnancy rates at intervals between >48 and 72 hours at
2.3% (95% CI, 1.4%–3.8%), >72 and 96 hours at 2.1% (95% CI, 1.0%–4.1%), and >96 and
120 hours at 1.3% (95% CI, 0.1%–4.8%). In a single-blind, comparative noninferiority
study of 1696 women, UPA was at least as effective as LNG when used within 72 hours
for EC, with 15 pregnancies in the UPA group and 22 pregnancies in the LNG group (odds
ratio = 0.68 [95% CI, 0.35–1.31]). In addition, UPA prevented significantly (P = 0.037) more pregnancies than LNG when used between 72 and 120 hours after unprotected
intercourse, with 0 pregnancies in the UPA group and 3 pregnancies in the LNG group.
In a meta-analysis, UPA prevented a greater percentage of pregnancies than LNG at
intervals up to 24 hours (0.9% UPA vs 2.5% LNG; P = 0.035), up to 72 hours (1.4% UPA vs 2.2% LNG; P = 0.046), and up to 120 hours (1.3% UPA vs 2.2% LNG; P = 0.025). The most commonly (>10%) reported adverse events included headache, nausea,
and abdominal pain. In addition, UPA delayed onset of menstruation by a mean of 2.1
to 2.8 days.
Conclusions
Based on clinical trials, UPA seems to be a reasonably tolerable and effective method
of EC when used within 120 hours of intercourse. UPA is at least as effective as LNG
when used within the first 72 hours after unprotected intercourse. However, UPA may
be more effective than LNG when used between 72 to 120 hours after unprotected intercourse,
extending the window of opportunity for EC. UPA may provide a new option for women
who require EC up to 5 days after unprotected intercourse.
Key words
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Article info
Publication history
Published online: December 12, 2011
Accepted:
November 4,
2011
Identification
Copyright
© 2012 Elsevier HS Journals, Inc. Published by Elsevier Inc. All rights reserved.
