Influence of seminal cryopreservation on embryo kinetics. Image analysis and clinical outcomes

This study aims to compare the effect of using fresh ejaculated sperm versus cryopreserved sperm on the morphology and kinetics of embryo development and on clinical reproductive outcomes.

Retrospective, observational, single-centre study conducted at IVIRMA Alicante (June 2013-December 2020) that included 469 oocyte donation cycles with frozen, fresh and mixed eggs in which ICSI, IVF or IVF-ICSI with fresh ejaculated and frozen ejaculated partner sperm was performed. For each group, the morphokinetic variables t2, t3, t4, t5, t6, t7, t8, tM, tSB, tB, tEB were studied in addition to the clinical pregnancy rate, implantation rate, ongoing pregnancy rate, miscarriage rate, and live birth rate, per transfer and per embryo transferred. Statistical analysis was performed using the IBM SPSS® software. Values of p≤0.05 were considered statistically significant.

Longer development times were observed in the fresh semen group, with significantly longer times for t2, t3, t4, t5, tB, tEB. Clinical results per transfer showed a trend, although not significant, towards lower rates in the cryopreserved semen group compared to the fresh semen group. However, the miscarriage rate was higher for the cryopreserved semen group, although this difference was not statistically significant.

Our results indicate that embryos from fresh semen have a slower developmental rate for the morphokinetic parameters studied. Since no significant differences in clinical reproductive outcomes were found, it is concluded that sperm freezing is a valuable technique that can continue to be applied. However, further studies are needed to confirm these results.