Comparison between Day 2 and Day 3 Embryo Transfer following in vitro Fertilization/Intracytoplasmic Sperm Injection

Aim: To compare reproductive outcomes of day 2 and day 3 embryo transfer (ET). Materials and methods: In this retrospective records study, all couples who underwent in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) and ET cycles at Lilavati Hospital & Research Centre over a period of 1 year were studied. Data were collected and analyzed by chi-square test and unpaired t-test by Statistical Package for the Social Sciences, version 16. Results: There was no statistically significant difference between the clinical and demographic parameters of group day 3 and day 2 ET. In our study, clinical pregnancy rate was 45% in day 3 ET and 36.5% in day 2 ET group [odds ratio (OR) 1.43, p-value 0.49]. The ongoing pregnancy rate was 39.2% in day 3 ET and 26.9% in day 2 ET group (OR 1.75, p-value 0.26). We observed that the miscarriage rate was 5.9% in day 3 ET and was 5.8% in day 2 ET group (p-value 0.69, OR 1.02). We observed one case each of multiple pregnancy, ectopic pregnancy, and fetal anomaly (anencephaly) in day 2 ET group, while in day 3 ET group, no such case was detected. Conclusion: There are chances that day 3 ET has better clinical and ongoing pregnancy rates than day 2 ET, but the difference is not statistically significant. Study showed similar miscarriage rates in both groups and very low incidence of complications like multiple pregnancy, ectopic pregnancy, and fetal anomaly. So, it is safe to schedule and transfer embryos either on day 2 or on day 3 for planning and programming cycles in coordination with patient and IVF team and for adjusting weekends (nonworking days). Clinical significance: Many steps of IVF procedure became standardized. However, the optimum timing of ET is still debatable. Several studies comparing ET on day 2 vs day 3 after oocyte retrieval have been performed, but the conclusions are conflicting. Despite development in culture media allowing blastocyst transfer, many centers still practice day 2/3 ET.