ABSTRACT
ObjectiveTo compare the effects of single sperm cryopreservation and conventional cryopreservation on embryo culture and pregnancy in patients undergoing microdissection testicular sperm extraction （micro-TESE）. MethodsA retrospective analysis was done on the patients who underwent micro-TESE at the Reproductive Medicine Center in the Sixth Affiliated Hospital of Sun Yat-Sen University between January 2018 and December 2021. The single sperm cryopreservation group included 39 patients undergoing single sperm cryopreservation and 307 MII oocytes. The conventional cryopreservation group included 39 patients undergoing conventional cryopreservation and 410 MII oocytes. Propensity score matching （PSM） was performed to balance the selection bias. The fertility rate， embryo culture and pregnancy of these two groups were compared. ResultsThere was no statistical difference in age， body mass index （BMI）， years of infertility， basal FSH， basal LH， basal E2， AMH， AFC， number of oocytes retrieved and number of transferred embryos between the two groups （P>0.05）. No significant difference was found in fertilization rate （65.8% vs. 60.49%）， available embryo rate （67.82% vs. 58.87%） and high-quality embryo rate （70.80% vs. 75.34%）. The single sperm cryopreservation group had significantly lower clinical pregnancy rate than conventional cryopreservation group （45.45% vs. 70.0%， P=0.049）. ConclusionIf the patients undergoing micro-TESE have very few sperms， single sperm cryopreservation could be an effective choice to increase the utilization of each sperm and ensure the subsequent sperm retrieval after thawing， but the clinical pregnancy rate is decreased. Due to the limited number of cases， we need a large additional number of cases to observe and analyze.
ABSTRACT
Sperm cryopreservation has been widely used in assisted reproduction, but conventional techniques are not suitable for the cryopreservation of small numbers of sperm. The application of the single sperm cryopreservation technique has significantly improved the clinical treatment of cryptozoospermia and non-obstructive azoospermia. Ever since Cohen et al first developed the method of single sperm cryopreservation in 1997, constant efforts have been made to develop the carriers for this technique. In this review, we mainly discuss the existing methods and clinical outcomes of single sperm cryopreservation.