Objective: To compare implantation and pregnancy rates in oocyte recipients undergoing a two-embryo versus three-embryo transfer, 3 days after retrieval.
Design: Retrospective comparative analysis.
Setting: University-based in vitro fertilization center.
Patient(s): All oocyte recipients undergoing embryo transfer from January 1, 1997 through August 31, 1999.
Intervention(s): Recipients received two or three embryos.
Main outcome measure(s): Implantation, and clinical and multiple pregnancy rates.
Result(s): Seventy-three recipients underwent a two-embryo transfer, and 376 had three embryos replaced. The numbers of oocytes retrieved (12.7 +/- 0.89 vs. 13.1 +/- 0.36) and embryos obtained (8.05 +/- 0.65 vs. 8.77 +/- 0.27) did not differ between the two-embryo and three-embryo transfer groups, nor did the proportion of patients with embryo cryopreservation (54.3% vs. 42.6%, respectively). There was no significant difference in pregnancy or implantation rates when comparing those patients with a two-embryo transfer to those with a three-embryo transfer. Significantly, 13.8% of the pregnancies in the three-embryo transfer group were triplet.
Conclusion(s): Reducing the number of embryos transferred in an oocyte donation cycle can lower the incidence of triplet pregnancies without significantly lowering the overall pregnancy rate.