Intracytoplasmic sperm injection does not improve the outcome of IVF treatments in patients with advanced maternal age or low oocyte number: A randomized controlled trial.

Abstract

Intracytoplasmic sperm injection (ICSI) was introduced to achieve fertilization in cases of severe male factor infertility. However, ICSI is often used in cases of non-male factor infertility, such as advanced maternal age or low oocyte number, but the clinical benefit of the method in these indications has not been proven. A prospective randomized study was conducted in a university clinic between 2018 and 2020. Patients with ≥40 years of age and/or ≤4 oocytes with non-sever male factor infertility were randomized into conventional IVF or ICSI groups. Fertilization rate, embryo quality, implantation, clinical pregnancy and live birth rates were compared. A total of 336 IVF cycles (169 conventional IVF and 167 ICSI) were involved in the study. The fertilization rate was higher in the conventional IVF group compared to the ICSI group (IVF: 61.7%, ICSI: 53.4%, P=0.001). Embryo development and morphology did not show considerable difference between groups. Implantation, clinical pregnancy and live birth rate were 13.1%, 24.3% and 11.4% in the conventional IVF and 10.4%, 19.0%, 12.0% in the ICSI group. The differences were not significant. Subgroup analysis showed a significantly better clinical outcome following conventional IVF when advanced maternal age was accompanied by low oocyte number (Implantation: 11.7% vs 2.6%, P=0.027; Clinical pregnancy: 18.5% vs 4%, P=0.020). A significantly higher fertilization rate, a tendency for higher clinical pregnancy rate was found in conventional IVF treatments compared to ICSI. When advanced maternal age was associated with low oocyte number, ICSI resulted in a substantially lower chance of fertilization and clinical pregnancy. These data suggest that ICSI offers no advantage over conventional IVF in terms of fertilization, embryo quality, implantation and pregnancy rates for couples with advanced maternal age or with low oocyte number.