Evaluating the convenience of natural cycle frozen embryo transfer
Official title: Assessing the Convenience of Natural Proliferative Phase Frozen Embryo Transfer: an Ambispective Cohort Study
Run by Instituto Valenciano de Infertilidade de Lisboa · NCT06307184 · Data updated 2026-11-12
This study looks at whether a new method for frozen embryo transfer that uses the body's natural cycle is easier and more convenient for patients compared to the traditional method that relies on medication.
Quick facts
| Study type | Observational |
|---|---|
| Ages | 18 Years to 49 Years |
| Sex | Women only |
| Enrollment | 530 (estimated) |
| Sponsor | Instituto Valenciano de Infertilidade de Lisboa Research network |
| Locations | 1 site (Lisbon) |
| Status | Recruiting |
| Started | February 23, 2024 |
| Main results expected | September 2026 |
| Study ends | December 2026 |
| Registry record updated | February 23, 2026 |
| Trial ID | NCT06307184 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates for this study are women with regular menstrual cycles who are undergoing their first or second frozen embryo transfer using a single blastocyst from donated oocytes.
✕Probably not a fit
Patients who have a history of recurrent pregnancy loss or implantation failure, or those requiring exogenous ovarian stimulation during the transfer, may not benefit from this study.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This observational study aims to assess the convenience of the natural proliferative phase frozen embryo transfer (NPP-FET) protocol by analyzing the number of appointments required before scheduling the transfer. The study compares NPP-FET with traditional artificial cycle frozen embryo transfer (AC-FET), which is often preferred for its scheduling ease despite potential risks associated with it. The research focuses on patients undergoing frozen embryo transfer in assisted reproductive technology (ART) clinics, particularly those using donated oocytes. By examining the convenience and outcomes of NPP-FET, the study seeks to provide insights into optimizing embryo transfer protocols.
Why it matters
Potential benefit: If successful, this study could lead to a more convenient and effective approach for patients undergoing frozen embryo transfers, potentially improving pregnancy outcomes.
How similar studies have gone: While there is growing evidence supporting the use of natural cycle protocols, this specific approach of NPP-FET is relatively novel and has not been extensively tested in prior studies.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Endometrial thickness ≥ 7 mm on the day of starting progesterone-based luteal phase support (LPS) * Serum progesterone levels \<1.5 ng/ml on the day of starting progesterone-based LPS * LPS with micronized progesterone 400mg b.i.d. * Regular cycles (\>24 days, ≤ 38 days) * IVF/ICSI with donated oocytes * Single blastocyst stage embryo transfer * First or second embryo transfer from the same cohort Exclusion Criteria: * Use of exogenous ovarian stimulation during FET * Untreated hydrosalpinx, polyp, submucous myomas or severe adenomyosis * Recurrent pregnancy loss (≥ 3 previous pregnancy losses) * Recurrent implantation failure with embryos from oocyte donation (≥ 3 previous failed embryo transfers) * Personalized initiation of exogenous progesterone according to a previous endometrial receptivity assay test
Where it's running
-
Instituto Valenciano de Infertilidade
Lisbon, Portugal Recruiting
Study contacts
- Principal investigator: Ana R Neves, MP — Instutito Valenciano de Infertilidade de Lisboa (IVI-RMA Lisboa)
- Study coordinator: Ana R Neves, MD, PhD
- Email: ana.neves@ivirma.com
- Phone: 218 503 210
Similar studies
Other studies for the same condition or treatment. Recruiting studies are listed first.
-
Measuring Relaxin Levels During Different Endometrial Preparation for Frozen Embryo Transfer
This study is testing how different methods of preparing the uterus for frozen embryo transfer affect the levels of a hormone called Relaxin in women to see if it impacts pregnancy success.
-
Comparing two methods for preparing the uterus for frozen embryo transfer in women with adenomyosis
This study tests two different ways to prepare the uterus for frozen embryo transfer in women with adenomyosis to see which one helps achieve more successful pregnancies.
-
Endometrial Waves and Pregnancy in FET Cycles with Hormone Therapy
This study tests whether patterns of uterine contractions during hormone-prepared frozen embryo transfer affect pregnancy outcomes.
-
Comparing two vaginal progesterone forms for frozen embryo transfer
This compares whether soft vaginal progesterone capsules are easier to use, better tolerated, and give similar pregnancy results as vaginal progesterone pessaries for women having frozen embryo transfer.
-
FET-LET-2x2: Testing natural vs medicated natural cycles for frozen embryo transfer
This study tests four approaches to preparing the uterus for frozen embryo transfer to see which yields the best pregnancy rate in women undergoing IVF.
-
How frozen embryo transfer preparation affects uterine wave activity
We will test whether preparing for frozen embryo transfer with hormones or using a natural cycle changes uterine contractions in women having FET.
How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.