Frozen-thawed day 5 blastocyst transfer is associated with a lower risk of ectopic pregnancy than day 3 transfer and fresh transfer

Objective: To determine the ectopic pregnancy rate with fresh versus frozen-thawed embryo transfers, and factors associated with ectopic pregnancy in patients undergoing IVF-ET. Design: Retrospective analysis. Setting: Institutional IVF center. Patient(s): A total of 3,183 patients who received 3,340 blastocysts transfers: 1,994 fresh transfers and 1,346 frozen-thawed transfers. Intervention(s): Patients received fresh day 3 embryos (F-D3 group), fresh day 5 blastocysts (F-D5 group), frozen-thawed day 3 embryos (T-D3 group), or frozen-thawed day 5 or 6 blastocysts (T-D5 and T-D6 groups). Main Outcome Measure(s): Ectopic pregnancy rate. Result(s): The ectopic pregnant rates were 2.4% in the F-D3 group, 1.7% in F-D5, 1.9% in T-D3, 0.3% in T-D5, and 0.5% in T-D6. The ectopic pregnant rate of the T-D3 group was significantly greater than that of the T-D5 and T-D6 groups (1.9% vs. 0.3% and 0.5%). The ectopic pregnancy rate of the F-D5 group was significantly greater than that of the T-D5 group (1.7% vs. 0.3%). Conclusion(s): Frozen-thawed day 5 blastocyst transfer is associated with a lower ectopic pregnancy rate than frozen-thawed day 3 transfer and fresh transfer in patients undergoing IVF-ET. ((c) 2015 by American Society for Reproductive Medicine.)