A Phase 4 interventional study of Ulipristal acetate in Contraceptive Usage, sponsored by Oregon Health and Science University. Recruiting at 1 site in United States. Open to female participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-09.
Sponsored by Oregon Health and Science University · Phase 4, Interventional, and Treatment
The purpose of this study is to learn more about why some people are at greater risk for oral emergency contraceptive failure while others are not. The investigators want to learn if genetic differences impact the risk of emergency contraception failure.
Each of us can respond differently to a drug or medication based on our genetics. An emergency contraceptive, ulipristal acetate or UPA, normally works by stopping or delaying the ovary from releasing an egg (ovulation). Our bodies break down UPA in order to use it through a system call the cytochrome P450 pathway but this pathway can be faster or slower depending on our genetics. The investigators want to learn more about how our individual genetic differences in this pathway change how the ovary responds to UPA. The overall goal of this research is to improve the effectiveness of emergency contraception for all people.
Exclusion Criteria:
Ulipristal acetate 30mg orally x 1 dose with pharmacokinetic and pharmacodynamics testing in individuals with active CYP3A5 alleles
Drug: Ulipristal acetate
Ulipristal acetate 30mg orally x 1 dose with pharmacokinetic and pharmacodynamics testing in individuals without active CYP3A5 alleles
Drug: Ulipristal acetate
Evaluating the pharmacodynamic and pharmacokinetic outcomes after 1 dose of Ulipristal acetate 30mg in individuals with and without active CYP3A5 alleles
Delay in follicular rupture
Follicular rupture (yes/no) by ultrasound. Defined as the disappearance of or \>50% reduction in size of the leading follicle
Time frame: over 1 menstrual cycle (assessed up to approximately 30 days)
Concentration of UPA
mean concentration maximum (Cmax) for UPA
Time frame: 5 days after taking study drug
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Oregon Health and Science University