The effect of artificial oocyte activation on blastocysts rate in patients with low blastocyst rates: A retrospective cohort study

Introduction Physiological oocyte activation requires a synergy between the oocyte and sperm to release calcium (Ca2+) through oscillations. The absence of such synergy between the oocyte and sperm leads to a negative impact on oocyte activation. Studies have shown that Artificial oocyte activation (AOA) is helpful in cases with failed or low fertilization rates. Studies present mixed opinions about increasing blastocyst rate. Methods A retrospective cohort single-center study was performed between January 2018 and October 2023, including 54 couples with suboptimal blastocyst development. The study compared intracytoplasmic sperm injection (ICSI) AOA cycles with previous conventional ICSI cycles and conventional ICSI without AOA cycles with previous conventional ICSI cycles in couples with failed or low blastocyst rates (< 30%) in the original ICSI cycle. Results We compared 22 AOA cycles to previous conventional ICSI cycles in the same patients and 32 conventional ICSI cycles without AOA to previous conventional ICSI cycles in the same patients. After AOA, the blastocyst rate was not significantly higher than the control group (48% vs 29% p=0.19). Conversely, the blastocyst rate was significantly higher in the conventional ICSI without AOA cycles than in the control group (48% vs 24% p=0.04). The fertilization rate was not statistically significant between the first and second cycles in both groups. Conclusion The literature still lacks strong evidence for AOA overcoming impaired embryonic development. Therefore, AOA remains reserved for couples with a failed or low fertilization history to improve fertilization results. Optimal laboratory conditions and ovarian stimulation modifications without AOA may improve blastocyst rates.