THE INCIDENCE OF MULTIPLE GESTATIONS AFTER IN-VITRO FERTILIZATION IS DEPENDENT ON THE NUMBER OF EMBRYOS TRANSFERRED AND MATERNAL AGE

Objective: To determine if the incidence of multiple gestations after IVF differs significantly depending on the number of embryos transferr ed and maternal age. Design: Retrospective analysis of IVF database. S etting: Tertiary care academic center. Patients: One thousand eight hu ndred sixty seven patients undergoing IVF with up to fbur embryos tran sferred during 1986 through 1993. Main Outcome Measures: The rate of s ingleton and multiple gestations >20 weeks estimated gestational age ( EGA). Results: The incidence of triplet gestations >20 weeks EGA among patients less than or equal to 34 years of age with three versus four embryos transferred was 0.3% (1/335) versus 2.4% (15/662), respective ly. The incidence of twin gestations >20 weeks EGA among patients less than or equal to 34 years of age with two versus four embryos transfe rred was 1.3% (3/234) versus 7.4% (46/622), respectively. Also among p atients less than or equal to 34 years of age, the incidence of single ton gestations >20 weeks EGA with two versus three embryos transferred was 12.8% (30/234) versus 15.8% (53/335); with two versus four embryo s was 12.8% (30/234) versus 17.2% (107/622); and with three versus fou r embryos was 15.8% (53/335) versus 17.2% (107/622), respectively. Con clusions: In women less than or equal to 34 years of age undergoing IV F-ET, the transfer of four versus three and four versus two embryos si gnificantly increased the incidence of triplet and twin gestations, re spectively, without significantly improving the chance of singleton co nception. This implies that a policy of transferring only three embryo s should be considered in this age group (realizing that such a policy may merit modulation if I,retransfer embryo selection is used.)