Day 4 versus day 3 embryo transfer: a prospective study of clinical outcomes

Objective

To compare the clinical outcomes after day 4 or day 3 embryo transfers in controlled ovarian hyperstimulation-IVF/intracytoplasmic sperm injection (ICSI) cycles.

Design

Prospective randomized study.

Setting

Center for Human Reproduction, ‘Genesis Athens’ Clinic (private gynecological and surgical clinic), Athens, Greece.

Patient(s)

Three hundred fifty women with primary infertility and indication for IVF/ICSI treatment. Patients were randomly allocated to day 4 or day 3 embryo transfer.

Intervention(s)

Controlled ovarian hyperstimulation, oocyte retrieval, IVF/ICSI, embryo transfer.

Main Outcome Measure(s)

Implantation rate; clinical, ongoing, and multiple pregnancy rates.

Result(s)

A trend toward higher clinical and ongoing pregnancy rates was noted after day 4 embryo transfers. Implantation and multiple pregnancy rates were comparable after day 4 or day 3 embryo transfers.

Conclusion(s)

The transfer of day 4 embryos in IVF/ICSI cycles may result in favorable implantation and pregnancy rates which are at least comparable to those after the transfer of day 3 embryos.

Key Words: Day 4 embryo transfer, day 3 embryo transfer, in vitro fertilization, assisted reproductive technologies