Last updated on September 2018

Impact of Combined Hormonal Contraceptives on UPA


Brief description of study

The purpose of this research study is to determine if taking a birth control pill effects how well an emergency contraceptive pill called Ulipristal acetate (UPA) works. This type of emergency contraceptive is the most effective oral method available. However, this medication is an anti-progestin and most regular forms of birth control contain progestin (a female hormone). It is unknown if taking the two close together may make the emergency contraceptive not work well. The overall goal of this research is to improve the effectiveness of contraception for women and to better counsel women.

Detailed Study Description

Emergency contraception (EC) provides women with an additional line of defense against unintended pregnancy during an act of unprotected intercourse. An antiprogestin, ulipristal acetate (UPA; ellaTM), has emerged as one of the most effective oral options. However, there is currently a lack of information regarding the practical use of UPA. Basic science studies have shown that UPA binds to and prevents progesterone receptor from working, leading to the possible concern that hormonal contraceptives, like the birth control pill, would prevent UPA from working. Ideally, women should start their regular method of birth control soon after EC use but by doing this, they may prevent the UPA EC from working. A woman could just delay starting her regular method of birth control but then she is still at risk for pregnancy. This proposal has been designed to address this gap in knowledge and will focus on the impact of the birth control pill on UPA's ability to delay ovulation (or the release of an egg). The hypothesis is that starting the birth control pill shortly after UPA adversely impacts UPA's ability to delay ovulation.

Clinical Study Identifier: NCT02577601

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Women's Health Research Unit

Oregon Health & Science University
Portland, OR United States