Your genes may determine if the Morning-After pill works
NCT ID NCT05674513
First seen Jul 09, 2026 · Last updated Jul 10, 2026 · Updated 1 time
Summary
This study investigates whether genetic differences affect how the body processes the emergency contraceptive ulipristal acetate, potentially explaining why some women experience contraceptive failure. Researchers will compare women with and without active CYP3A5 genes, measuring drug levels and ovulation timing after a single dose. The goal is to understand if inherited traits influence emergency contraception effectiveness.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Ulipristal acetate
- What this could lead to
- If successful, this could help identify women at higher risk of emergency contraceptive failure and guide more personalized contraceptive choices.
- What could go wrong
- This is a small Phase 4 study focused on biological mechanisms, not a large efficacy trial. Results may not change clinical practice immediately.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 4
Runs after approval, following long-term safety and how well the treatment works in everyday use.
- Participants
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About 140 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Jan 2023
- Expected to finish
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Dec 2027
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 40 years
- Sex
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Female participants only
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
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
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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OHSU
RECRUITINGPortland, Oregon, 97239, United States
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