Evaluating the time interval between oocyte retrieval and micro testicular sperm extraction: a single-center retrospective cohort study.

PURPOSE: To evaluate the embryological and clinical outcomes of couples undergoing micro testicular sperm extraction (TESE) at 24 h or 48 h before oocyte retrieval and intracytoplasmic sperm injection (ICSI).

METHODS

We conducted a retrospective study of 129 ICSI cycles using sperm recovered by micro-TESE from a single fertility center between June 2015 and January 2025. Patients were stratified according to timing of oocyte retrieval following micro-TESE: 24 h (n = 104) vs. 48 h (n = 25). Baseline demographics, including age, hormonal profile, and degree of sperm concentration (non-obstructive azoospermia, cryptozoospermia, or severe oligoasthenoteratozoospermia), were collected. Embryological outcomes included the number of retrieved oocytes, mature oocytes (MII), fertilization rate, and blastocyst formation (2PN). Clinical outcomes assessed were biochemical pregnancy, clinical pregnancy, and live birth rates.

RESULTS

Baseline characteristics did not differ significantly between groups. Of note, given the retrospective nature of the study, we could not control for factors such as oocyte quality, protocol variations, and reasons for a delayed cycle. Embryological outcomes, including fertilization rate (67% vs. 65%; p = 0.81) and blastocyst rate (50% ± 26 vs. 49% ± 29; p = 0.90), were comparable between the 24-h and 48-h groups. However, significant differences were observed in clinical outcomes: positive β-hCG rates were higher in the 24-h group (72% vs. 35%; p = 0.002)), as were clinical pregnancy rates (65% vs. 35%; p = 0.01) and live birth rates (56% vs. 30%; p = 0.03).

CONCLUSION

Although prior studies have shown that sperm culture up to 48 h may enhance motility, the current study demonstrates that an extended culture may be associated with less favorable clinical outcomes. Our findings demonstrate that oocyte retrieval within 24 h of micro-TESE was associated with higher clinical pregnancy and live birth rates compared to longer culture intervals. Given the retrospective design, these findings should be interpreted cautiously, and prospective randomized studies are needed to better define the optimal timing between micro-TESE and oocyte retrieval.