ICSI is an advanced form of IVF, mainly used to overcome infertility due to severe defects in semen parameters. It is also used if patient has repeated fertilization failures after conventional IVF, or when sperms are surgically retrieved.
Difference between IVF and ICSI
ICSI is mainly an embryological procedure. The initial procedure including ovarian stimulation, oocyte retrieval, and embryo transfer remains the same in both techniques. The two techniques differ in the lab procedure. In conventional IVF, after oocyte retrieval, a calculated number of sperms are laid around each egg and the sperm penetration and fertilization has to happen on its own, whereas in ICSI a good quality sperm is selected and is directly injected inside the oocyte through a micro-injection technique using a micromanipulator under high magnification microscope as we need only one sperm per egg, the number of sperms required for the procedure is as equal to the number of eggs retrieved. The fertilized eggs are then transferred to the incubator and allowed to grow. The remaining procedure is the same as IVF.
The eggs are also processed differently for ICSI, as they are first cleaned and denuded to remove surrounding cells. The eggs are screened for maturity under a microscope and only the mature ones (M2) can be used for ICSI.
Indications for ICSI
- Men with low sperm count, poor motility or morphology.
- In cases with surgically retrieved sperms like MESA, TESA, TESE.
- In patients with recurrent fertilization failure with IVF.
- In patients undergoing preimplantation genetic diagnosis.