A retrospective analysis of artificial oocyte activation in patients with low or no fertilisation in intracytoplasmic sperm injection cycles

Abstract

Intracytoplasmic sperm injection (ICSI) is commonly used to treat severe male factor infertility in assisted reproduction. A small percentage of patients face suboptimal fertilisation rate or even fertilisation failure despite having ICSI. Artificial oocyte activation (AOA) has been proposed as a suitable method to overcome their problem. This is a retrospective cohort analysis of ICSI cycles undergoing AOA. Injected metaphase II oocytes were exposed to either calcium ionophore (A23187) after ICSI or injection of calcium chloride during ICSI followed by incubation with A23187 after ICSI. The previous ICSI cycles of the patients formed the historical control group. Thirty-four AOA cycles were analysed. The normal fertilisation rate (52.1%) was significantly improved in the AOA group. The percentage of failed fertilisation cycles (11.8%) were significantly reduced in the AOA group. The cumulative clinical pregnancy rate (47.1%) and live birth rate (29.4%) were significantly increased when compared to the previous cycles. Subgroup analysis revealed that the performance of the A23187 only protocol and the concomitant injection of calcium chloride protocol were comparable in terms of laboratory parameters and pregnancy outcomes. AOA is an effective method to improve the fertilisation rate and pregnancy outcome of infertile couples with previous fertilisation problem after ICSI.

IMPACT STATEMENT

• What is already known on this subject? A failed and low fertilisation rate after ICSI is not uncommon in assisted reproduction. AOA is normally used to improve fertilisation but there are discrepancies in the efficacy of the treatment.

• What do the results of this study add? AOA improves the fertilisation rate and pregnancy outcomes of couples with suboptimal fertilisation rate and fertilisation failure in previous ICSI cycles. The efficacies of two AOA protocols were comparable. The A23187 only protocol was recommended because of its simplicity.

• What are the implications of these findings for clinical practice and/or further research? AOA should be considered as a routine procedure for infertile couples with compromised fertilisation rates in previous ICSI cycles.

Keywords:

• ICSI
• assisted reproduction technology
• oocyte activation
• fertilisation

Acknowledgements

The authors acknowledge the laboratory staff at both centres for their excellent work and technical support.

Ethics approval

The study protocol was reviewed and approved by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster (Ref. no. UW 20-639).

Author contributions

All authors had full access to the data, contributed to the study, approved the final version for publication and take responsibility for its accuracy and integrity. Concept of the study: KKW Lam and WSB Yeung. Acquisition of data: KKW Lam, JYY Wong and TM Cheung. Analysis and interpretation of data and drafting of the manuscript: KKW Lam. Critical revision for important intellectual content: EHY Ng, WSB Yeung and RHW Li.

Disclosure statement

All authors have disclosed no conflicts of interest.

Additional information

Funding

This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.