Transdermal versus oral estrogen: clinical outcomes in patients undergoing frozen-thawed single blastocyst transfer cycles without GnRHa suppression, a prospective randomized clinical trial

PURPOSE: To conduct a non-inferiority study to compare the clinical outcomes of transdermal estrogen patch and oral estrogen in patients undergoing frozen-thawed single blastocyst transfer non-donor cycles without GnRHagonist (GnRHa) suppression. METHODS: A total of 317 women with irregular menses or anovulatory cycle undergoing frozen-thawed embryo transfer (FET) non-donor cycles without GnRHa suppression were involved in a prospective randomized clinical trial between May 2017 and October 2017. The trial was conducted in an ART and Reproductive Genetics Centre within a private hospital. The unit is designated as a teaching center by the Turkish Ministry of Health. Oral or transdermal estrogen was administered in patients undergoing frozen-thawed single blastocyst transfer. The outcomes of the study were the following: endometrial thickness on the day of progesterone administration, implantation rate, and clinical and viable ongoing pregnancy rates. RESULTS: Endometrial thickness and clinical outcomes of oral and transdermal estrogen administration were equally successful (p > 0.05). CONCLUSION: No significant difference was found in endometrial thickness on the day of progesterone administration nor in clinical outcomes between transdermal estrogen and oral estrogen in patients undergoing frozen-thawed single blastocyst stage transfer cycles without GnRHa suppression.