Safety evaluation of frozen-thawed embryo transfer in artificial cycles

Abstract

Objective To evaluate the safety of frozen-thawed embryo transfer (FET) in artificial cycles. Methods A retrospective study was conducted on 1397 cycles of FET which comprised two groups:an artificial cycle group using the artificial cycle treatment (Estradiol Valerate tablets plus Progesterone injection,420 cycles) and a natural cycle group using the natural cycle treatment (the control group,977 cycles). All the cycles were completed in our hospital between January 2004 and June 2008. The rates of clinical pregnancy,implantation,delivery,abortion,ectopic pregnancy,multiple pregnancy,low-birth-weighted singletons,premature-delivered singletons and birth defects were compared between two groups,so as to evaluate the safety of frozen-thawed embryo transfer (FET) in artificial cycles. Results There were no significant differences between the artificial and natural cycle groups with regard to the rates of clinical pregnancy[26.2 % (110/420) vs 23.9% (233/977)],implantation[13.7% (142/1034) vs 12.6% (299/2369)],delivery[69.1% (76/110) vs 76.0% (177/233)],abortion[22.7% (25/110) vs 18.0% (42/233)],ectopic pregnancy[2.7% (3/110).vs 3.0 % (7/233)]multiple pregnancy[26.4% (29/110) vs 24.9% (58/233)],low-birth-weighted singletons[1.6% (1/63) vs 4.4% (6/138)],prematurely delivered singletons[9.5% (6/63) vs 7.3% (10/138)],birth defects[0% (0/420) vs 0% (0/977)],delivery of male neonates[53. 8% (43/80) vs 54. 2% (96/177)]and delivery of female neonates[46.2% (37/80) vs 45.8% (81/177)](all P>0.05). Conclusion FET in artificial cycles can be safe in the near future evaluation. Key words: Embryo transfer; Pregnancy rate ; Implantation rate; Artificial cycles; Natural cycles