Day-3 vs. Day-5 fresh embryo transfer.

Objective: Embryo transfer on day-5 has been associated with higher success rates, therefore our IVF clinics started to extend embryo culture until blastocyst stage. This study aimed to compare the success rates of day-3 vs. day-5 embryo transfers.

Methods: We had 266 patients included, all having undergone ICSI, with 221 patients having undergone day-3 embryo transfers, and 45 patients having undergone day-5 embryo transfers. Patients with more than five good quality embryos on day-3 were chosen to prolong the culture of embryos into day-5.

Results: There were no significant differences in patient characteristics, including baseline LH, FSH, Prolactin and Estradiol hormone levels. In addition, there were also no significant differences in rFSH total dosage and duration of stimulation day. Final estradiol levels, number of follicles, retrieved oocytes, matured oocytes, fertilized oocytes and number of embryos were significantly higher in day-5 compared to day-3 embryo transfer groups. Number of embryos transferred on day-3, were significantly higher compared to day-5. Neither group showed any significant differences in clinical pregnancy, implantation, multiple pregnancy or living birth rates. There were no differences in birth weights and lengths, head circumstances and Apgar Scores between both groups either in singleton or twin group.

Conclusions: Transferring embryos at day-3 may provide the same benefits as day-5 embryo transfers to patients. However, more embryos were required to be transferred to achieve these comparable results.