ObjectiveEmbryo 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.MethodsWe 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.ResultsThere 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.ConclusionsTransferring 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.