It is the best option in cases where the husband’s sample is of low quality or very low quantity, therefore predicting low chances of fertilizing the eggs on their own. It is also the option for cases of failure to fertilize in IVF. In this method sperm is injected inside the cytoplasm of the egg, and once the eggs are fertilized and the embryos cleave, embryos are transferred back to the uterus on day 2, day 3 or day 5 as in IVF-ET.
ICSI is the last resort for severe male factors including obstructive azoospermia (absence of sperms in semen), in which sperm may also be retrieved surgically from either the epididymis (PESA) or from the testes (TESA/TESE). An azoospermic man can father a child provided sperm is retrieved from his testes.