Effects of two kinds of endometrial preparation protocols on pregnancy outcomes of frozen-thawed embryo transfer

Abstract

Objective To compare the clinical pregnancy outcomes of two kinds of endometrial preparation protocols in frozen-thawed embryos transfer (FET). Methods Chose 947 FET cycle as the research subjects in Reproductive Medicine Center of Northern Jiangsu People′s Hospital from June 2010 to June 2015. The 501 FET cycles which took endometrial preparation protocol of natural cycles were included in the natural cycle group, and the 446 FET cycles which took endometrial preparation protocol of artificial cycle were included in the artificial cycle group. The clinical medical records of two groups were retrospectively analyzed. The general clinical data, clinical pregnancy outcomes and differences of clinical pregnancy rates of different age subjects between subjects of two groups of FET cycles were compared statistically. Results ①There were no significant differences between two groups of FET cycles in general clinical data, including age, duration of infertility, endometrial thickness on transplantation day, basal estrogen and progesterone concentrations, basal follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels, and the number of transplantation embryos (P>0.05). ②There were no significant differences between two groups of FET cycles in clinical pregnancy outcomes, including embryo implantation rate, clinical pregnancy rate, ectopic pregnancy rate, miscarriage rate and live birth rate (P>0.05); ③There were no significant differences between two groups of FET cycles in the clinical pregnancy rates in age of ≤30 and >30-35 years old women, however, the clinical pregnancy rate in age of >35-40 years old women of natural cycle group was higher than that of artificial cycle group, and the difference was statistically significant (χ2=5.011, P=0.025). Conclusions Natural cycle and artificial cycle of endometrial preparation protocols have no obvious different effects on pregnancy outcomes of FET. But for age >35-40 years old women, natural cycle may be superior to artificial cycle for FET. Key words: Cryopreservation; Embryo transfer; Menstrual cycle; Pregnancy outcomes; Female