Ovulation can be stimulated by one of several regimens. The drugs used include: clomiphene citrate (Clomid™, Serophene™, oral medications), hCG (Pregnyl, Ovidrel™, Luveris®), human menopausal gonadotropin or FSH (Follistim™, Gonal F™,Bravelle™). These drugs are given by subcutaneous injection rather than intramuscularly. Clinics often use one or several of these drugs. A GnRH agonist (Lupron™, Synarel™) or GnRH antagonist (Ganirelix Acetate Injection™, Cetrotide™) can also be prescribed to prevent a premature surge in the hormone LH. Some clinics start the GnRH agonist in the luteal phase of the cycle preceding the IVF attempt; others just prior to ovulation induction. The drug is given by subcutaneous injection or nasal spray. In contrast, the GnRH antagonists are given once the stimulation drugs are started.
If injectable, ovulatory inducing drugs are being given, frequent blood samples to check estrogen levels may be drawn. By day 5, estrogen levels often are over 100 pg/ml. Vaginalultrasound is used to monitor the growth, size and number of developing ovarian follicles. Ideally, estradiol levels should be at least 400 pg/ml. and ultrasound should show at least 2 follicles with a diameter of 16-17 millimeters or greater before hCG is given. The ripened eggs will be released in 38-40 hours after this injection.