Artificial oocyte activation after intracytoplasmic morphologically selected sperm injection: A prospective...

This study aimed to evaluate the effect of artificial oocyte activation (AOA) by calcium ionophore after intracytoplasmic morphologically selected sperm injection (IMSI) on fertilization, cleavage rate and embryo quality. A total of 194 oocytes from 21 cycles from women with a history of low fertilization rate accompanying teratozoospermia were enrolled over a 3-month period. Mature oocytes from each patient were randomly allocated into two groups after IMSI. In the study group, half of the patients' oocytes (n = 97) were exposed to AOA, and in the control group (n = 97), AOA was not applied. The mean number of mature oocytes, fertilization and cleavage rates were similar between the study and control groups (p > 0.05 for each). However, fertilized oocytes of the AOA group were less likely to produce top quality embryos when calculated per fertilized oocyte (28/80; 35.0% versus 38/71; 53.5%, respectively; p = 0.024) and also per cycle (13/21; 61.9% versus 20/21; 95.24%, respectively; p = 0.006). Our study indicates that AOA may not improve fertilization rates after IMSI and may even reduce the ability of a successfully fertilized oocyte to develop into a top quality embryo. AOA should, therefore, be applied to cases with a defined oocyte activating deficiency.