Comparison of ivf and pregnancy outcomes in frozen embryo transfers on day 3, advanced from day 3 to day 5, and on day 5

Comparison of IVF and pregnancy outcomes in frozen embryo transfers on day 3, advanced from day 3 to day 5, and on day 5 AIM: In FET cycles, we aimed to observe the impact of embryo transfer days on pregnancy outcomes. We compared the transfer outcomes of embryos frozen and transferred on day 3, embryos frozen on day 3 and advanced to day 5, and embryos frozen and transferred on day 5 MATERIALS AND METHODS: Between January 2017 and January 2024, the files of all patients over 25 and under 45 years old who underwent frozen-thawed embryo transfer at the Assisted Reproductive Techniques Center of Sakarya University Faculty of Medicine were reviewed. Subsequently, among these patients, the pregnancy and live birth outcomes of those who had day 3 embryos frozen and advanced to day 5 in the thaw cycle, those who had day 3 embryos frozen and transferred after thawing, and those who had day 5 embryos frozen and transferred after thawing were compared. RESULTS: No statistically significant differences were observed among the patient groups in terms of age, BMI, transfer age, transfer day, number of embryos transferred, endometrial thickness, duration of infertility, FSH, AMH, PRL, TSH, and T4 (P˃0.05). The D3 FET group showed statistically significant differences in pregnancy and live birth rates. The D3-5 and D5 FET groups had similar pregnancy and live birth rates. CONCLUSION: Pregnancy and live birth rates of FET cycles where embryos were thawed on day 3 and advanced to day 5 are better than those of day 3 FET cycles and are similar to those of day 5 FET cycles.