P-027 Sperm motility and calcium ionophore treatment influence fertilization and pregnancy outcomes in TESE-ICSI
Authors: Pock T , Fechtmann K , Plester E , Sperlbaum T , Behre H  M , Kliesch S , Nordhoff V 
Published: July 2024

Abstract

Study question
Are there differences in fertilization and pregnancy rates post-TESE-ICSI between motile and immotile sperm, and do these vary in treatments with and without calcium ionophore?

Summary answer
Post-TESE-ICSI data reveals differences in fertilization and pregnancy rates when comparing motile vs. immotile sperm and treatments with and without calcium ionophore after TESE-ICSI.

What is known already
Testicular sperm extraction (TESE) followed by intracytoplasmic sperm injection (ICSI) poses a challenge for every IVF laboratory. This is particularly true in patients exhibiting azoospermia, where only a few and mostly immotile sperm are present in testicular tissue. In these cases, a calcium ionophore treatment for activation of the oocyte may help to overcome poor prognosis fertilization outcome, and thereby enhancing the likelihood to achieve a transfer leading to a successful pregnancy. Although both techniques, TESE-ICSI and activating substances are commonly applied, detailed analyses for individual counselling of couples are missing.

Study design, size, duration
This study analyzed 787 TESE-ICSI cycles (2015-2023) regarding patient age, number of attempts, oocyte maturity, fertilization and pregnancy rate after fresh embryo transfer. Cycles were split into four groups: (A) at least one motile sperm was injected (n = 493); (B) only immotile sperm were used (n = 294); (C) calcium ionophore (n = 474); (D) no calcium ionophore (n = 313). 17 cycles were excluded from the study because no sperm were found on the day of TESE-ICSI and oocytes were vitrified.

Participants/materials, setting, methods
In our IVF clinic, calcium ionophore treatments are only offered if a pre-screening of TESE samples reveals the absence of motile spermatozoa or if a previously conducted TESE-ICSI attempt resulted in a low fertilization rate (&lt;30%) or a total fertilization failure. Statistical analyses was performed to compare the motile and immotile sperm group and the groups with or without calcium ionophore treatment.

Main results and the role of chance
No differences were found in all groups (A-D) regarding age of female or male patient and number of collected oocytes per group. However, our results demonstrate a difference in the mean number of ICSI attempts when comparing motile sperm and immotile sperm (2.0±1.3 vs. 2.3±1.6, p &lt; 0.05), and when comparing attempts with calcium ionophore treatment and those without (2.4±1.6 vs. 1.8±1.8, p &lt; 0.0005). The mean fertilization rate (2PN stage) was higher in the motile sperm group (A) compared to the immotile group (B) (57.8% vs. 28.4%, p &lt; 0.0005) and also higher in attempts of group (D) in comparison to attempts of group C (56.8% vs. 40.2%, p &lt; 0.0005). While fertilization failure occurred less often in group (A) (3.2%) it occurred to a higher rate in group (B) (19.4%), followed by group (C) (12.0%). Biochemical (BPR) and clinical pregnancy rates (CPR) showed a significant difference between the motile and immotile sperm group (BCR: 33.2% vs. 12.3%, p &lt; 0.0005; CPR: 25.6% vs. 9.3%, p &lt; 0.0005), but no differences between the two calcium ionophore groups.

Limitations, reasons for caution
This analysis was done retrospectively. A potential subgroup analysis of groups (A) and (B) into calcium ionophore use and of groups (C) and (D) into motile or immotile sperm will reveal the effect of calcium ionophore on success rates regardless of sperm motility.

Wider implications of the findings
Our data provides insight into success rates of TESE-ICSI cycles, especially if only immotile sperm were present. This will serve as a helpful guide for physicians when counseling patients about their success rates and to optimize the outcome in cases with poor prognosis by using a calcium ionophore treatment.

Trial registration number
not applicable