Understanding how genetics affect emergency contraception effectiveness

Disparities in Emergency Contraceptive Metabolism Dictate Efficacy

Phase 4 Interventional Oregon Health and Science University · NCT05674513

This study is trying to see if genetic differences affect how well the emergency contraceptive ulipristal acetate works for different people.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment140 (estimated)
Ages18 Years to 40 Years
SexFemale
SponsorOregon Health and Science University Academic / other
Locations1 site (Portland, Oregon)
Trial IDNCT05674513 on ClinicalTrials.gov

What this trial studies

This study investigates the reasons behind varying effectiveness of the emergency contraceptive ulipristal acetate (UPA) among individuals, focusing on genetic differences that may influence drug metabolism. By examining how the cytochrome P450 pathway affects the breakdown of UPA, researchers aim to determine the relationship between genetic variations and ovulation response to the medication. The ultimate goal is to enhance the efficacy of emergency contraception for diverse populations.

Who should consider this trial

Good fit: Ideal candidates for this study are generally healthy women aged 18-40 with regular menstrual cycles.

Not a fit: Patients who are pregnant, breastfeeding, or have irregular menstrual cycles will not benefit from this study.

Why it matters

Potential benefit: If successful, this research could lead to more effective emergency contraception options tailored to individual genetic profiles.

How similar studies have performed: While the study explores genetic factors in emergency contraception, similar approaches have shown promise in other areas of pharmacogenomics, indicating potential for success.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Generally healthy women
* Aged 18-40
* regular menses (every 21-35 days) experiencing ovulatory cycles proven by a single progesterone level of 3 ng/mL or greater during the luteal phase of the screening cycle.

Exclusion Criteria:

* Pregnant, seeking pregnancy, or breastfeeding
* Known allergy to study medication
* Recent use of hormonal contraception
* Irregular periods (\<21 days or \>35 day cycles)
* Routine use of nonsteroidal anti-inflammatory drugs
* Metabolic disorders
* Smoking
* Any condition that would preclude the provision of informed consent
* Using drugs (within 2 weeks of study enrollment) known to interfere with the metabolism of UPA as well as drugs known to be CYP3A4 inducers, inhibitors, or CYP3A drug substrates

Where this trial is running

Portland, Oregon

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Contraceptive UsageUlipristal acetateEmergency contraception
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.