Comparison of pregnancy and neonatal outcomes of intracytoplasmic sperm injection performed with frozen versus fresh testicular sperm

BACKGROUND: It remains controversial whether there is a difference in the prognosis of intracytoplasmic sperm injection (ICSI) using frozen or fresh testicular sperm in patients with obstructive azoospermia (OA). Moreover, in the available studies, few have tracked neonatal outcomes. This study aimed to compare the pregnancy and neonatal outcomes of ICSI using cryopreserved sperm versus fresh sperm collected by testicular sperm aspiration (TESA). METHODS: A total of 317 OA patients treated with ICSI in a university affiliated hospital from January 2016 to December 2020 were included in this study. The participants were divided into two groups according to the type of sperm used for ICSI: frozen sperm group (n=154) and fresh sperm group (n=163). The pregnancy and neonatal outcomes of the two groups were compared. RESULTS: The data produced by this study showed no significant statistical difference in the 2 pronuclei (2PN) fertilization rate, 2PN cleavage rate, high-quality blastocyst rate, and the average number of transferred embryos in the frozen and fresh sperm groups. Similarly, no difference was found in implantation rate, clinical pregnancy rate, multiple pregnancy rate, miscarriage rate, premature delivery rate, live birth rate, and gender ratio at birth (P>0.05). The average newborn birth weight was similar in both groups (2,932.61±728.40 vs. 3,100.32±515.64 g, respectively) (P>0.05). A higher incidence of low birthweight (LBW) newborns was found in the frozen sperm group (20.91% vs. 8.49%) (P<0.05). Multiple logistic regression analysis showed that LBW is related to single or twin pregnancies (P<0.01), but not sperm (frozen or fresh) (P>0.05). We further analyzed the twin and single pregnancies in the two groups separately, and found that the incidences of LBW were both similar (P>0.05). There was no difference in the Apgar scores at 1 min and 5 min after birth between the two groups (P>0.05). CONCLUSIONS: The use of frozen testicular sperm by TESA was efficient for men with OA. There were similar pregnancy and neonatal outcomes following TESA-ICSI using frozen or fresh sperm in this retrospective study. Prospective investigations are needed for further validation.