How long can the sperm wait? Effect of incubation time on ICSI outcomes

Abstract

In sperm processing for IVF/ICSI incubation times differ considerably both between and within assisted reproduction facilities. There is no established consensus on the optimal sperm incubation timings to maximize pregnancy rates, and the few studies addressing this association rely on manual and operator-dependent methods for time recording. The present retrospective cohort study includes 1169 ICSI cycles using fresh semen processed by swim-up. An operator-independent, radiofrequency-based system was used to record sperm incubation times: from sample collection to swim-up (T1, 0.35 ± 0.26); from swim-up to ICSI (T2, 3.30 ± 2.2); and total time from sample collection to ICSI (T, 3.66 ± 2.26). In oocyte donation cycles, we observed a significant negative effect of T1 on fertilization rate (FR; generalized linear modelling regression, coeff. −0.20, p = 0.001); however, after analysing all times by deciles and by adjusted logistic regression, none of the time intervals had a significant effect on pregnancy (biochemical, clinical, and ongoing) and live birth (LB) rates (p > 0.05 for all outcomes). In cycles using the patient's oocytes, we observed a negative effect of T2 (ordinal regression, coeff. −0.25, p = 0.011) and T (−0.33, p = 0.005) on the mean morphological score of the embryo cohort. In these cycles, a trend associating longer values of T with higher LB rates was identified (OR = 1.47, p = 0.050), although this difference is likely not clinically significant. In conclusion, while longer sperm incubation in vitro may impact slightly both FRs and embryo morphology after ICSI, no adverse effects were detected on the reproductive outcomes.

Extend the Survival of Human Sperm In Vitro in Non-Freezing Conditions: Damage Mechanisms, Preservation Technologies, and Clinical Applications

“…However, a prospective multicenter cohort study revealed that sperm preparation time in the range of 40–80 min may result in the optimal pregnancy rate [ 152 ]. When it comes to ICSI, several studies observed that no adverse effects were detected on the reproductive outcomes within 5 h [ 9 , 12 , 103 ]. Overall, it suggested that performing IUI or IVF/ICSI immediately after semen collection may be preferable, but the delayed insemination is apparently a feasible alternative for men who are unavailable to provide sperm on the day of oocyte retrieval [ 37 ].…”

“…Some studies proposed that hypothermic preservation can be a substitute for cryopreservation if spermatozoa could be obtained surrounding the day of ART [ 10 , 11 ]. Besides, sperm acquired for ART undergo a prolonged incubation in artificial gamete or embryo cultural media, which may compromise its fertility [ 12 , 13 ]. Optimization of the sperm’s functional competence during this period is supposed to improve the clinical outcome of ART [ 14 , 15 ].…”