Progesterone level on embryo transfer day and pregnancy after frozen embryo transfer

Impact of Serum Progesterone Levels on Embryo Transfer Day on Clinical Pregnancy in Frozen-thawed Embryo Transfer Cycles Using Hormone Replacement Therapy: a Prospective Observational Study

Observational Chinese University of Hong Kong · NCT07388797

We will test whether blood progesterone levels on the day of embryo transfer affect the chance of clinical pregnancy for people having hormone-replacement frozen-thawed embryo transfers.

Quick facts

Study typeObservational
Enrollment370 (estimated)
Ages18 Years to 42 Years
SexFemale
SponsorChinese University of Hong Kong Academic / other
Locations1 site (Hong Kong)
Trial IDNCT07388797 on ClinicalTrials.gov

What this trial studies

This observational study will record serum progesterone levels on the day of embryo transfer in HRT-FET cycles and categorize patients by those levels. Clinical pregnancy rate is the primary outcome, with biochemical pregnancy, implantation rate, early pregnancy loss, and ectopic pregnancy as secondary outcomes. Eligible participants are infertility patients aged 18–41 with BMI under 30 who transfer at least one good-quality embryo; patients with severe untreated endocrine or uterine conditions are excluded. All procedures and sample collection occur at The Chinese University of Hong Kong and outcomes will be compared across progesterone level groups.

Who should consider this trial

Good fit: Infertility patients aged over 18 and under 42 with BMI under 30 who are undergoing hormone-replacement frozen embryo transfer and transferring at least one good-quality embryo are ideal candidates.

Not a fit: Patients with severe untreated endocrine disorders or significant untreated uterine pathology, those outside the age/BMI limits, or those not using HRT-FET are unlikely to benefit from these findings.

Why it matters

Potential benefit: If a clear relationship is found, progesterone measurement on transfer day could be used to better time or tailor luteal support and improve pregnancy chances in HRT-FET cycles.

How similar studies have performed: Previous observational studies on progesterone levels at transfer have reported mixed results, so this study builds on existing but not definitive evidence.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patients undergoing FET cycles
* Infertility patients aged \>18 years old and \< 42 years old
* BMI \< 30 kg/m2
* Transfer of at least one good-quality embryo.

Exclusion Criteria:

* Severe endocrine disorders (e.g., thyroid dysfunction, premature ovarian failure).
* Severe uterine factors without treatment (severe endometriosis, extensive or subendometrial fibroid, uterine adherent, endometrial polyps)

Where this trial is running

Hong Kong

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 Reproductive Issues
Last reviewed 2026-06-13 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.