Calcium ionophore improves embryonic development and pregnancy outcomes in patients with previous developmental problems in ICSI cycles

BACKGROUND: Calcium (Ca(2+)) ionophores are now mainly considered as efficient treatments for fertilization failure. Recently, its application for rescuing poor embryo development was proposed but still non-routine. This study aimed to explore whether Ca(2+) ionophore improves embryo development and pregnancy outcomes in patients with poor embryo development in previous intracytoplasmic sperm injection (ICSI) cycles. METHODS: This study included 97 patients undergoing assisted oocyte activation (AOA) with Ca(2+) ionophore (calcimycin, A23187) treatment. Preimplantation embryonic development and clinical outcomes were compared between ICSI-AOA cycles (AOA group) and previous ICSI cycles of the same patients in which poor embryo developmental potential was present (non-AOA group). Subgroups stratified by maternal age (< 35, 35–40, ≥ 40 years, respectively) were analyzed separately. RESULTS: A total of 642 MII oocytes were collected in AOA group, and 689 in non-AOA group. Significantly higher day 3 good quality embryo rate (P = 0.034), good quality blastocyst formation rate (P < 0.001), and utilization rate (P < 0.001) were seen in AOA group. Similar results were seen in each subgroup. For pregnancy outcomes, there were significant differences in clinical pregnancy rate (P = 0.039) and live birth rate (P = 0.045) in total group. In subgroup aged < 35 years, biochemical (P = 0.038), clinical (P = 0.041), and ongoing pregnancy rate (P = 0.037) in AOA group were significantly higher than that in non-AOA group. No significant improvement for clinical outcomes for subgroups aged 35–40 and aged ≥40. CONCLUSION: The study suggests that calcimycin could improve preimplantation development and pregnancy outcomes in patients aged < 35 years with embryo developmental problems in previous ICSI cycles. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12884-022-05228-3.