Your genes may determine if the Morning-After pill works

NCT ID NCT05674513

What the study statuses mean

This study's is highlighted.

Recruitment status, easiest to join first

Recruiting now This study
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

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

Phase 4

Runs after approval, following long-term safety and how well the treatment works in everyday use.

Participants

About 140 people

The number the study aims to enrol. It can still change while the study runs.

Started

Jan 2023

Expected to finish

Dec 2027

An estimate. End dates often move.

Lead sponsor

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

18 to 40 years

Sex

Female participants only

Healthy volunteers

Accepted

You do not need to have the condition being studied to take part.

Show 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.

Contraception Behavior

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.

  1. The places running it

    1 site. The list below names each one and where it is.

  2. 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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  3. 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

  • OHSU

    RECRUITING

    Portland, Oregon, 97239, United States

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