Day 2 vs. day 3 embryo transfer after intracytoplasmic sperm injection. A prospective, randomized study

Abstract

Objective: To compare, in a prospective, randomized study, implantation and pregnancy rates between day 2 and day 3 embryo transfer intracytoplasmic sperm injection (ICSI).

Study design: A total of 106 patients undergoing ICSI cycles who had at least 1 embryo suitable for cryopreservation were prospectively randomized into 2 groups: group I, embryo transfer performed on day 2; group II, embryo transfer performed on day 3.

Results: Patient ages did not differ (P = .58) between groups I (33.1 +/- 4.5) and II (32.7 +/- 4.4). The number of oocytes retrieved from group I (13.7 +/- 5.2) was similar (P = .82) to that retrieved from group II (13.7 +/- 5.4). In addition, there was no difference (P = .30) in the number of oocytes retrieved at metaphase II between groups I (10.6 +/- 4.4) and II (9.7 +/- 4.2). Fertilization and cleavage rates were also similar (P = .58 and P = .50, respectively) between groups I (78.2 +/- 14.0% and 98.7 +/- 4.3%) and II (76.2 +/- 14.8% and 99.8 +/- 1.24%, respectively). The total number of embryos and of embryos transferred were similar (P = .22 and P = .36; respectively) for groups I (8.0 +/- 3.0, 2.8 +/- 0.7) and II (7.16 +/- 3.2, 2.6 +/- 0.8). Pregnancy rates per transfer, implantation rates and abortion rates were also similar for groups I (43.4%, 20.8% and 8.7%, respectively) and II (41.5%, 24.1% and 23%, respectively) (P = 1.0, P = .57 and P = .24, respectively).

Conclusion: The results suggest that extending the embryo culture period from 2 to 3 days for patients who had at least 1 embryo left for cryopreservation had no effect on implantation, pregnancy or abortion rates in an ICSI program.