During ovarian stimulation, induction, the hormones for egg growth and rupture, are given to stimulate multiple eggs to grow in the ovaries rather than one egg, so that the chance of getting a genetically normal egg capable of forming a normal baby is higher.
There are different methods if stimulating the ovary. The natural LH surge is prevented by the administration of drugs like GnRH agonists or antagonists so that the eggs can be picked up at the right time. The entire cycle has to be done under careful supervision with ultrasound as the chance of ovarian hyperstimulation is high.