Clinical outcomes of fresh and frozen embryos transfer after in vitro fertilization in spouses of patients with severely low sperm count and motility.

Abstract

To compare the pregnancy and neonatal outcomes of in vitro fertilization-embryo transfer (IVF-ET) with fresh or frozen embryos for male patients with severely low sperm count and motility. A total of 2300 male patients with severely low sperm count and motility underwent IVT-ET in the Reproduction Medicine Center, Sir Run Run Shaw Hospital from April 2018 to April 2022. After applying the propensity score matching (PSM), 473 fresh embryo transferred cycles and 473 frozen embryo transferred cycles were selected in the study, and the pregnancy and neonatal outcomes were compared between two groups. There were no significant differences in pregnancy outcomes and neonatal outcomes between fresh and frozen embryo groups (all P>0.05). In the stratification analysis, the number of retrieved oocytes in the fresh good-quality embryo transfer group was significantly increased compared with the fresh poor-quality embryo group (P<0.05), but the very early pregnancy loss rates were similar between the two groups, while the rate in fresh good-quality embryo transfer group was significantly higher than that in the frozen good-quality embryo transfer group (P<0.05). Among different age groups of women, the number of retrieved oocytes and the level of estrogen in the fresh embryo transfer group was significantly higher in the 20 to <30 years old group than that in the 30 to <35 years old group (both P<0.05), but the clinical pregnancy rate was lower in the 20 to <30 years old group than that in the 30 to <35 years old group (P>0.05). Additionally, the very early pregnancy loss was significantly increased in the fresh embryo group compared with the frozen embryo group in the 20 to <30 years age group (P<0.05). There is no significant difference in pregnancy and neonatal outcomes between fresh embryo transfer and frozen embryo transfer for male patients with severely low sperm count and motility undergoing IVF-ET. Due to shorter transfer time, less embryo freezing damage and reduced costs, fresh embryo transfer can be considered a first choice. However, it is not necessary to pursue fresh embryo transfer if maternal oestrogen levels are too high and there is a tendency of overstimulation.