Clinical outcomes of two different endometrial preparation methods for cryopreserved‐thawed embryo transfer in patients with a normal menstrual cycle

Aim: To compare the clinical outcomes of cryopreserved‐thawed embryo transfer among patients with a normal menstrual cycle who had natural or hormone‐replacement cycles. Methods: From January 2004 to June 2006, cryopreserved embryos following conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) were thawed and transferred in a total of 720 natural cycles and 136 hormone‐replacement cycles. Results: Cryopreserved‐thawed embryo transfer in patients who had a natural or hormone‐replacement cycle resulted in clinical pregnancy in 43.1% and 40.4%, respectively; a rate of miscarriage of 14.5% and 23.6%, respectively; and a rate of ongoing pregnancy and delivery of 36.5% and 30.9%, respectively. None of these differences were statistically significant. Conclusions: Patients with a normal menstrual cycle who have natural or hormone‐replacement cycles can be expected to have comparable clinical outcomes with cryopreserved‐thawed embryo transfer. (Reprod Med Biol 2007; 6 : 53–57)