IVM involves retrieving immature oocytes (eggs) from the ovaries and culturing them in a specialized medium until they reached maturity. Once mature, they are fertilized with sperms using ICSI. Compared to mature size follicle (≥14 mm), it is more difficult to retrieve eggs from intermediate size follicles (≤10 mm) and not all of these eggs can reach maturity in vitro; furthermore, in vitro matured eggs have a lower fertilization rate as well. Because of the high wastage, IVM is more suited to women with polycystic ovarian disease (PCOD) whereby the risk of ovarian hyperstimulation syndrome (OHSS) can be minimized.