Emergency Contraception Options: Focus on Ulipristal Acetate

摘要

Ulipristal acetate (UPA) is a progesterone receptor modulator that is available for emergency contraception (EC) and can be taken up to 120 hours after unprotected intercourse. A meta-analysis of clinical trials comparing UPA with levonorgestrel (LNG) for EC, demonstrated that UPA has higher efficacy than LNG. This higher efficacy is supported by biomedical studies that have demonstrated that UPA is a more potent inhibitor of ovulation, being able to delay ovulation in the immediate preovulatory period, when LNG is no longer effective. A recent study that explored risk factors for failure of EC, demonstrated that obese women were at increased risk of EC failure, with either UPA or LNG. However, failure was significantly less amongst women receiving UPA than those receiving LNG. There is growing evidence therefore, that UPA should be the preferred oral method of EC.