Effect of freezing and thawing on ejaculated sperm and subsequent pregnancy and neonatal outcomes in IVF.

Background: Techniques for sperm cryopreservation have exhibited their potential in male fertility preservation. The use of frozen-thawed sperm in Methods: This retrospective cohort study at a tertiary-care academic medical center included 447 women who used paternal frozen-thawed ejaculated sperm and 31,039 women who used paternal freshly ejaculated sperm for IVF and underwent frozen-thawed blastocyst transfer from January 2011 to September 2021. To balance the baseline characteristics of the two groups, patients using frozen sperm were matched with control groups using a propensity score matching algorithm with a ratio of 1:3. Results: Although sperm motility decreased from 82.04% to 75.70% (P < 0.001) after the freezing-thawing process, the fertilization rate (68.27% for frozen sperm and 67.54% for fresh sperm), number of viable embryos (1.98 and 2.16), clinical pregnancy rate (44.7% and 51.8%), and live birth rate (40.3% and 42.4%) were comparable between the two groups (all P > 0.05). For neonatal outcomes, no between-group differences were observed in offspring gender, gestational age, birthweight, and the rate of preterm birth (21.7% and 12.9%), low birthweight neonates (19.2% and 16.0%), and birth defects (0.0% and 0.8%) (all P>0.05). Conclusions: Frozen-thawed sperm had lower sperm motility but resulted in comparable embryonic, pregnancy, and neonatal outcomes versus fresh sperm in IVF cycles.