Fine Paul M
Womens Health (Lond). 2011 Jan;7(1):9-17. doi: 10.2217/whe.10.63.
Ulipristal acetate (UPA), a selective progesterone receptor modulator, when taken as a single 30-mg dose, is safe and effective for emergency contraception up to 5 days (120 h) following unprotected intercourse. This indication has been approved in Europe since May 2009 and was approved by the US FDA in August 2010. The older progesterone-only emergency contraceptive, levonorgestrel (LNG), is approved only up to 72 h after unprotected intercourse. UPA is effective in delaying or inhibiting ovulation, even if taken 24 to 48 h prior to expected ovulation, a time when LNG is no longer effective. A recent meta-analysis of two randomized clinical trials showed UPA to have a pregnancy risk 42% lower than LNG up to 72 h, and 65% lower in the first 24 h following unprotected intercourse. In a randomized trial enrolling women up to 5 days after unprotected intercourse, significantly more pregnancies were prevented with UPA than with LNG when taken beyond 72 h.
醋酸乌利司他（UPA）是一种选择性孕激素受体调节剂，单次服用30毫克剂量时，对无保护性交后长达5天（120小时）的紧急避孕安全有效。该适应症自2009年5月起在欧洲获得批准，并于2010年8月获得美国食品药品监督管理局（FDA）批准。较老的仅含孕激素的紧急避孕药左炔诺孕酮（LNG）仅在无保护性交后72小时内获批。UPA可有效延迟或抑制排卵，即使在预期排卵前24至48小时服用也有效，而此时LNG已不再有效。最近对两项随机临床试验的荟萃分析表明，在长达72小时内，UPA的妊娠风险比LNG低42%，在无保护性交后的头24小时内低65%。在一项纳入无保护性交后长达5天女性的随机试验中，在72小时后服用时，UPA预防的妊娠显著多于LNG。
