Oocyte Activation by Calcium Ionophore and Congenital Birth Defects: a Retrospective Cohort Study

Objective: To evaluate the safety of oocyte activation by calcium ionophore in cases of failed fertilization after intracytoplasmic sperm injection (ICSI) procedure with respect to birth defects.

Design: A retrospective cohort of pregnancies achieved by oocyte activation with calcium ionophore after ICSI (ICSI-Ca) and routine ICSI between the years 2006 and 2014.

Setting: Not applicable.

Patient(s): The cohort included a total of 793 pregnancies: 66 (8%) were lost to follow up and 49 (6%) were ongoing pregnancies at the time of data collection. Out of the 678 available cases for analysis, 595 treatments were ICSI alone (88%) and 83 were ICSI-Ca (12%).

Intervention(s): None.

Main Outcome Measure(s): Pregnancy and neonatal outcomes including birth defects were compared.

Result(s): On the basis of a cohort of 595 ICSI pregnancies and 83 ICSI-Ca pregnancies, we found no difference in birth defects rate for singletons or for twins. Additionally, no significant difference was found between defect type (chromosomal aberration or structural malformations) and malformation type (heart, urogenital, and limb), between the ICSI and ICSI-Ca groups. Moreover, no significant differences were found regarding birth weight, gestational week at time of delivery, and fetal gender for singleton or twin pregnancies.

Conclusion(s): Ca ionophore oocyte activation should be considered as a legitimate option for cases of failed or low fertilization by ICSI.