Assisted oocyte activation (AOA)

Assisted oocyte activation uses a brief chemical exposure, most often a calcium ionophore, alongside ICSI to help trigger the biological steps of fertilisation in eggs that have previously failed to activate normally. It is considered for couples with a documented history of very low or absent fertilisation despite ICSI, rather than used routinely. The evidence on assisted oocyte activation is still developing, and Indian clinical guidance does not describe it as a standard step for most IVF cycles; where it is offered, it should be explained as an additional technique with an uncertain overall benefit for pregnancy or live birth, discussed on an individual basis with your embryology and clinical team.

Also known as: AOA, calcium ionophore, oocyte activation

Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.