Comparing immediate and postponed embryo transfer for infertility treatment
Official title: Immediate Versus Postponed Single Blastocyst Transfer in Programmed or Stimulated Cycle Frozen Embryo Transfer: a Multicenter Randomized Controlled Trial
Run by Copenhagen University Hospital, Rigshospitalet · NCT06304792 · Data updated 2026-11-12
This study is testing whether transferring an embryo right after egg retrieval is just as effective as waiting to transfer it later for helping people with infertility have a baby.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 18 Years to 40 Years |
| Sex | Women only |
| Enrollment | 484 (estimated) |
| Sponsor | Copenhagen University Hospital, Rigshospitalet Academic / other |
| Locations | 1 site (Copenhagen) |
| Status | Recruiting |
| Started | February 1, 2024 |
| Main results expected | August 1, 2028 |
| Study ends | August 1, 2028 |
| Registry record updated | August 11, 2025 |
| Trial ID | NCT06304792 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates include women eligible for frozen embryo transfer following a fresh embryo transfer or freeze-all cycle, including both ovulatory and oligo-anovulatory women.
✕Probably not a fit
Patients with uterine malformations, severe reproductive health issues, or those requiring oocyte donation 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 randomized controlled trial aims to determine if immediate single blastocyst transfer after oocyte retrieval is as effective as postponed transfer in achieving live births. The study will include 484 patients who will be randomly assigned to either immediate or postponed frozen embryo transfer (FET) in a multicenter setting. Participants will undergo assessments and treatments based on their randomization, with the primary outcome being the live birth rate. The trial is set to run from February 2024 to August 2028.
Why it matters
Potential benefit: If successful, this study could provide insights into optimizing embryo transfer timing, potentially improving live birth rates for patients undergoing IVF.
How similar studies have gone: Other studies have explored embryo transfer timing, but this specific comparison of immediate versus postponed transfer is relatively novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Eligible for FET in a programmed- or stimulated cycle immediately following a fresh embryo transfer or freeze all cycle * Oligo-anovulatory women (cycle length \> 35 days) * Ovulatory women (cycle length 21-35 days) * At least one vitrified day 5 or 6 blastocyst with Gardner score of ≥ 3BB at the day of vitrification Exclusion Criteria: * Uterine malformation * Presence of hydrosalpinx, submucosal uterine myomas or uterine polyps * Allergies or contraindication to standard fertility medication * Male or female HIV or Hepatitis B or C * Preimplantation genetic testing (PGT) in the fresh cycle * Testicular sperm aspiration (TESA) * Severe OHSS with hospital admission and ascites drainage during the fresh cycle * Oocyte donation
Where it's running
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Fertility Departmen, Rigshospitalet
Copenhagen, Denmark Recruiting
Study contacts
- Study coordinator: Anja B Pinborg, Prof., DMSC
- Email: anja.bisgaard.pinborg@regionh.dk
- Phone: 0045 35 45 64 30
Similar studies
Other studies for the same condition or treatment. Recruiting studies are listed first.
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Pentoxifylline to improve uterine lining and frozen embryo transfer outcomes
This trial sees if giving pentoxifylline alongside standard estradiol helps women with good-quality day‑5 frozen embryos get a thicker uterine lining and better frozen embryo transfer success.
-
Aromatherapy to support mental health in women undergoing IVF
This will test whether inhaling lavender oil twice daily can reduce anxiety, stress, and depression and improve quality of life for women awaiting IVF.
-
In vitro maturation of human eggs for fertility treatment
This study is testing a new way to help women with fertility issues by maturing their eggs in the lab with fewer hormones to see if it makes treatment easier and safer.
-
Examining discarded materials from IVF cycles to understand treatment outcomes
This study is trying to see if analyzing leftover materials from IVF cycles can help predict which treatments will be successful and improve the chances of pregnancy.
-
Selecting sperm for gender-specific offspring
This study is testing a new way to choose sperm based on whether it carries an X or Y chromosome to help couples undergoing infertility treatment have a baby of a specific gender.
-
Long-term follow-up for patients using preimplantation genetic testing
This study is trying to learn about the long-term experiences and outcomes of people who have used preimplantation genetic testing during IVF to help improve care in reproductive genetics.
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.