Ovulation induction for IVF entails administering gonadotropins with a GnRH agonist or antagonist to allow for the development of multiple eggs and prevent premature ovulation. The stimulation is monitored with blood work and ultrasounds. Hormone levels are measured with the blood work (estradiol, progesterone, LH) and the size of the follicles is measured to ascertain oocyte maturity. When a cohort of follicles are developed a trigger injection is given, either HCG or Leuprolide acetate, to start the process of ovulation. A trans vaginal oocyte retrieval is then performed 35-36 hours later.