Day‑3 (cleavage) versus day‑5–7 (blastocyst) embryo transfer for IVF patients with few embryos
Day 3 Versus Day 5 Embryo Transfer in IVF Patients With Few Embryos
PHASE3 · Beth Israel Deaconess Medical Center · NCT06746129
This test compares whether transferring embryos on day 3 (8‑cell cleavage stage) or waiting until day 5–7 (blastocyst) leads to better pregnancy and live birth outcomes for people having their first IVF cycle who produce five or fewer embryos.
Quick facts
| Phase | PHASE3 |
|---|---|
| Study type | Interventional |
| Enrollment | 1126 (estimated) |
| Ages | 18 Years to 44 Years |
| Sex | Female |
| Sponsor | Beth Israel Deaconess Medical Center (other) |
| Locations | 1 site (Boston, Massachusetts) |
| Trial ID | NCT06746129 on ClinicalTrials.gov |
What this trial studies
This randomized Phase 3 trial will enroll about 1,126 people aged 18–44 undergoing their first autologous IVF cycle who have five or fewer embryos. Participants are randomly assigned to receive a fresh embryo transfer either at the cleavage stage (day 3) or after culture to blastocyst stage (day 5–7). Any surplus embryos that meet freezing criteria may be cryopreserved and used in later thaw cycles according to standard practice. Investigators will follow patients to compare pregnancy and live birth outcomes between the two timing strategies across multiple U.S. IVF centers.
Who should consider this trial
Good fit: Ideal candidates are people aged 18–44 having their first autologous IVF cycle with ≤5 zygotes on day 1 who plan a fresh embryo transfer and do not meet exclusion criteria like planned PGT or uterine factor infertility.
Not a fit: Patients who have more than five embryos, plan universal preimplantation genetic testing, use a gestational carrier, have significant uterine factors, or who convert to an all‑freeze cycle are unlikely to benefit from this trial.
Why it matters
Potential benefit: If successful, the results could help clinicians choose the transfer timing that maximizes live birth chances and minimizes unnecessary multiple pregnancies for patients with few embryos.
How similar studies have performed: Observational and prior trials suggest advantages to blastocyst transfer in broader IVF populations, but randomized evidence specifically for patients with few embryos is limited, making this question relatively untested in that subgroup.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * autologous IVF cycle * ≤5 zygotes on day 1 of development * Fresh embryo transfer Exclusion Criteria: * Planned preimplantation genetic testing (PGT) of all embryos * More than 2 previous IVF cycles * History of recurrent pregnancy loss (≥3) * Body mass index \>40 * Presence of uterine factor infertility * Planned gestational carrier * Endometrial lining \<6mm measured on the day of trigger * Lupron-only trigger, elevated progesterone in the fresh cycle (≥1.5ng/ml) * Delayed fertilization (\>18 hours) * Rescue intracytoplasmic sperm injection (following failed regular fertilization) * Use of non-ejaculated sperm (testicular sperm extraction) * Embryo transfer number outside American Society of Reproductive Medicine (ASRM) guidelines * Cycle is converted to a cycle in which all embryos are frozen
Where this trial is running
Boston, Massachusetts
- Boston IVF — Boston, Massachusetts, United States (RECRUITING)
Study contacts
- Principal investigator: Werner Neuhausser, MD PhD — Beth Israel Deaconess Medical Center/Harvard Medical School
- Study coordinator: Beatrice Duvert
- Email: bduvert@bidmc.harvard.edu
- Phone: 617-975-7632
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions: Infertility, infertility, in vitro fertilization, cleavage stage embryo, blastocyst, embryo transfer