The relationship between the hormone levels before transplantation and the outcomes of hormone replacement therapy frozen embryo transfer

BACKGROUND: The aim of the present study was to analyze the relationship between the outcomes of hormone replacement therapy frozen embryo transfer (HRT-FET) and serum estradiol and progesterone levels on the day of endometrial transformation and before transplantation. METHODS: Clinical data of patients who underwent 426 cycles of HRT-FET were retrospectively analyzed and were divided into group according to estradiol and progesterone levels. Differences in embryo implantation rate and clinical pregnancy rate were compared, and relationship between estradiol levels and outcome of transplantation was analyzed. RESULTS: During the 426 cycles, clinical pregnancy rate was 49.77% and embryo implantation rate was 27.20%. Differences in estradiol and progesterone levels on the day of endometrial transformation and before transplantation between pregnant and non-pregnant groups were not statistically significant. Furthermore, embryo implantation rate and clinical pregnancy rate among different levels of estradiol patients was not statistical different. On the day before transplantation, serum estradiol level decreased in 98.36% of patients. Differences in implantation rate and clinical pregnancy rate among patients with different extents of decrease in estradiol and different progesterone levels the day before transplantation were statistically significant (P<0.05). CONCLUSIONS: The extent of decrease in serum estradiol and progesterone levels on the day before transplantation may be associated with outcome of HRT-FET.