In this procedure, the oocyte is prepared by removing its outer coat of cells called the cumulus complex. Once laid bare, the oocyte is held gently by a holding pipette under an inverted microscope.
The sperm that has been prepared for microinjection is injected through a very fine micropipette into the cytoplasm (body) of the oocyte.
The oocyte holding pipette and the injection pipette are 20 and 60 times thinner than human hair respectively. The microinjected egg is returned to the incubator and checked the following day for fertilization.
This procedure is ideally suited in cases of very low sperm counts (oligozoospermia) or zero count (azoospermia), very little (asthenospermia) or complete lack of motility and abnormal shape of the sperm (teratozoospermia).
Its use is extended to women with advanced age, women suffering from endometriosis and those with immunological and unexplained infertility.