A two- versus three-embryo transfer: the oocyte donation model

Objective: To compare implantation and pregnancy rates in oocyte recipients undergoing a two-embryo versus three-embryo transfer, 3 days after retriev al. 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 37 6 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, n or did the proportion of patients with embryo cryopreservation (54.3% vs. 4 2.6%, respectively). There was no significant difference in pregnancy or im plantation rates when comparing those patients with a two-embryo transfer t o those with a three-embryo transfer. Significantly, 13.8% of the pregnanci es in the three-embryo transfer group were triplet. Conclusion(s): Reducing the number of embryos transferred in an oocyte dona tion cycle can lower the incidence of triplet pregnancies without significa ntly lowering the overall pregnancy rate. (C) 2001 by American Society for Reproductive Medicine.