P-218 Does Artificial Oocyte Activation (AOA) improve the outcome beyond fertilization rate in ICSI cycles?
Authors: Beltramo M L , Cantwell N , Hogan R , Sanchez A , Ojo T , Gibbons C , Salvatore L 
Published: June 2023

Abstract

Study question
Does CultActive© improve reproductive outcomes of ICSI cycles in cases of low fertilization rate and normal fertilization rate?

Summary answer
The application of CultActive© after ICSI improves fertilization rates only in clinical indication of fertilization failure.

What is known already
Oocyte activation deficiency is attributed in the majority of cases to fertilization failure in ICSI cycles, and these can be corrected by increasing initial levels of calcium (Ca2+) using assisted oocyte activation techniques (AOA), such as the use of Ca2+ ionophores. These agents enhance intracellular calcium release and increase the membrane permeability facilitating the influx of extracellular Ca2+, which initiates the activation cascade. Previous results suggest that Ca2+ ionophore treatment can increase the live birth rate after failed ICSI cycles in couples with poor fertilization rates, embryo developmental arrest, and also increase the number of good quality embryos.

Study design, size, duration
This was a retrospective observational study. There were 30 patients included and the first group consisted of 30 ICSI cycles, 231 oocytes and 56 embryos (without AOA). The second group consisted of the same patients (n = 30) with 30 ICSI cycles using AOA, 219 oocytes and 47 embryos. Subgroups were defined according to clinical indications (normal fertilization rate group: ≥ 65 % and low fertilization rate group: &lt;65% ). All data was collected from January-December 2022.

Participants/materials, setting, methods
450 oocytes were assessed in the study. 231 oocytes belonged to the pre-AOA and 219 belonged to the AOA. The oocytes were exposed for 15 minutes after ICSI in a solution containing the Ca2+ ionophore A23187, CultActive© (Gynemed, Germany). Fertilization, good quality blastocyst formation and pregnancy rate were analyzed.Good quality blastocyst were defined as ≥ 3BB. Statistical significance was analyzed using the Paired Student T test (p &lt; 0.05 was considered statistically significant).

Main results and the role of chance
The cohort of patients with normal fertilization rate (without clinical indications),was not significantly different. The AOA treatment gave a fertilization rate of 61% compared to 71% of the control cycles (p = 0.1398). There was no increase in the number of good quality blastocysts formation when the study group was compared to the control (p = 0.1660). In the cohort of patients with an indication of low fertilization, a significantly higher fertilization rate was recorded compared to the control (51% and 37%, respectively p = 0.0238). There were no significant difference in the quantity of good quality blastocysts compared with the control (p = 0.3328). Regardless of normal or low fertilization rates there was no significant difference in pregnancy rate when CultActive© was used in treatment (p &gt; 0.05).

Limitations, reasons for caution
There are limitations in our study. First, the retrospective design and limited study population are major limitations. The data should be interpreted cautiously in the subgroup analyses due to potential bias, specifically the small population in the group without clinical indication.

Wider implications of the findings
AOA was only beneficial for couples with poor fertilization. Embryo quality and pregnancy rate did not improve with CultActiveive©. External variation was minimized by using the same patients in each cohort. This suggests AOA should not be used without clinical indication or for poor embryo quality/blastulation rate.

Trial registration number
not applicable