Using etonogestrel implant for emergency contraception

Etonogestrel Implant as Emergency Contraception: A Pilot Pharmacodynamic Study

PHASE4 · University of Colorado, Denver · NCT05237141

This study is testing if an etonogestrel implant can work as emergency contraception by preventing ovulation when it's inserted before a certain hormone surge in women with regular menstrual cycles.

Quick facts

PhasePHASE4
Study typeInterventional
Enrollment12 (estimated)
Ages18 Years to 40 Years
SexFemale
SponsorUniversity of Colorado, Denver (other)
Locations1 site (Aurora, Colorado)
Trial IDNCT05237141 on ClinicalTrials.gov

What this trial studies

This study evaluates the effectiveness of the etonogestrel implant as a method of emergency contraception by inserting it before the luteinizing hormone (LH) surge. It is a single-site, open-label pilot study that will assess ovulation rates through serum hormone levels and transvaginal ultrasound after the implant is placed. The hypothesis is that the implant can inhibit ovulation if inserted prior to the LH surge, leveraging the rapid hormonal changes associated with the implant. Participants will be women with regular menstrual cycles who desire the implant for contraception.

Who should consider this trial

Good fit: Ideal candidates are women with regular menstrual cycles who are not currently pregnant and wish to use the etonogestrel implant for contraception.

Not a fit: Patients with known hypersensitivity to etonogestrel or those with medical conditions affecting liver function may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could provide a new method of emergency contraception that is effective and timely.

How similar studies have performed: This study is novel as there have been no prior studies specifically evaluating the etonogestrel implant for emergency contraception in this manner.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* BMI less than or equal to 28kg/m2
* Intact uterus with at least one ovary
* Regular menstrual cycles that occur every 21-35 days
* If patient is postpartum or post-second trimester abortion, 3 menses (2 cycles) must have occurred prior to enrollment
* If patient had a first trimester abortion or pregnancy loss, she must have one spontaneous menses prior to enrollment
* Desires insertion of an etonogestrel contraceptive implant for contraception
* Not currently pregnant or trying to become pregnant
* Willing to abstain from medications and supplements known to induce/inhibit CYP3A4 during the study

Exclusion Criteria:

* Have a known hypersensitivity or contraindications to etonogestrel.
* Medical conditions that affect liver function (e.g., hepatitis, cirrhosis; assessed via participant self-report)
* Known or suspected current alcohol dependence syndrome or any illicit drug use that may affect the metabolism of the etonogestrel.
* Uncontrolled thyroid disorder.
* Use of long-acting injectable hormonal contraceptive within the past 9 months
* Current use of hormonal oral, patch, intravaginal, or intrauterine contraception

Where this trial is running

Aurora, Colorado

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.

View on ClinicalTrials.gov →

Conditions: Contraception

Last reviewed 2026-05-15 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.