Comparing Day 5 and Day 6 Embryo Transfers for Pregnancy Rates

Impact of a Predetermined Day 5 Embryo Transfer Versus a Predetermined Day 6 Embryo Transfer on the Clinical Pregnancy Rate After Intracytoplasmic Sperm Injection (ICSI) Treatment

Infertility Treatment Center Dortmund · NCT06447077

This study is testing whether transferring embryos on day 5 or day 6 after treatment can lead to higher pregnancy rates for people undergoing fertility treatment.

Quick facts

Study typeObservational
Enrollment2400 (estimated)
Ages18 Years and up
SexFemale
SponsorInfertility Treatment Center Dortmund (other)
Locations1 site (Dortmund, North Rhine-Westphalia)
Trial IDNCT06447077 on ClinicalTrials.gov

What this trial studies

This prospective multicenter study aims to compare the clinical pregnancy rates of predetermined embryo transfers on day 5 versus day 6 after ICSI treatment. The study will involve patients undergoing single embryo transfers at three fertility centers in Germany. The primary endpoint is the detection of a gestational sac per embryo transfer, while the secondary endpoint focuses on the abortion rate per clinical pregnancy. This research seeks to determine if a day 6 transfer could provide advantages in embryo development assessment.

Who should consider this trial

Good fit: Ideal candidates are women aged 18 and older undergoing their first ICSI cycle with a single embryo transfer.

Not a fit: Patients who are not undergoing ICSI treatment or those requiring multiple embryo transfers may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could optimize embryo transfer timing, potentially increasing pregnancy rates for patients undergoing ICSI treatment.

How similar studies have performed: While previous studies have compared day 4 and day 5 transfers, this is the first prospective study examining the equivalence of day 5 versus day 6 transfers.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion criteria:

The patients to be included should be ≥18 years old. There is no upper age limit. Only ICSI treatments with a single embryo transfer (SET) should be included. Only the first cycle per patient should be evaluated.

Exclusion criteria:

none

Where this trial is running

Dortmund, North Rhine-Westphalia

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: Infertility, Reproductive Issues, ICSI, Predetermined Day 6 Embryo Transfer, Predetermined Day 5 Embryo Transfer

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.