In vitro fertilization (IVF) involves the fertilization of eggs by sperm in a dish (outside the woman's body). The embryos which result are transferred back into the woman's body (ET).Although it is technically possible to perform IVF without the use of fertility drugs, only one egg would be collected and the chance for pregnancy would be low. With the use of fertility drugs many eggs (ova)are retrieved, improving the chances of success.	Photo Slideshow: A Look Inside IVF
Injectable gonadotropins are used for most IVF procedures. In order to arrive at an ideal starting point a cycle of oral contraceptive pills is often prescribed prior to beginning gonadotropin injections. In addition, many patients are pretreated with a gonadotropin releasing hormone (GnRH) agonist (for example Lupron,a drug that turns off a patient's own hormones). The GnRH agonist down-regulation allows injectable gonadotropins to synchronize the development of multiple follicles. GnRH agonists also prevent a woman from triggering her ovulation prematurely (before the eggs can be collected).Alternatively,a GnRH-antagonist medication may be utilized beginning a few days before oocyte collection, in order to prevent premature egg release.

In a typical IVF cycle the woman begins a package of oral contraceptive pills on or before the fifth days of her period. On the 18th day of that cycle injections of Lupron are begun. A period is expected around day 26. An ultrasound and blood tests are then performed to verify that the woman is in a good "starting position" to receive the injectable gonadotropin drugs.

The dose of gonadotropins ( taken daily or twice daily) is adjusted with hopes of obtaining 12 to 15 oocytes (eggs) for use during the IVF procedure. Progress towards ovulation is monitored every few days with ultrasound and blood tests. If she has not been treated with Lupron, the woman will begin the medication Ganerelix after ultrasound has determined that her leading follicle is 12-14mm. in size. When the patient's follicles are ripe, ovulation is triggered with an injection of human chorionic gonadotropin (hCG).

Thirty-seven and a half hours after the hCG injection eggs are retrieved by passing a needle alongside a vaginal ultrasound probe into the ovaries. Intravenous sedation assures that the patient feels no pain. The patient's follicles are aspirated . An embryologist identifies eggs within the follicle fluid. The eggs are placed in a dish with sperm that the husband has produced around the time of the procedure

On the day after the retrieval the embryologist evaluates the number and quality of newly fertilized embryoes. Spare embryos may be frozen for use in future cycles. The remaining embryos are cultured for transfer back into the woman's uterus between two and six days after ovum retrieval. In special situations the growing embryoes are biopsied so that abnormal embryoes may be excluded (PGD).

The embryo transfer (ET) is a simple procedure which requires no anesthesia. The number of embryos transferred back into the patient is chosen in a way to balance the risk of multiple gestation against the risk of not conceiving . In some cases the embryos are partially liberated from the natural membrane that surrounds them (zona hatching) in order to facilitate implantation. Injections of progesterone are taken daily to "support" the implantation process. About two weeks after the eggs were retrieved blood tests are performed to determine whether or not pregnancy has successfully occurred.The early pregnancy will be followed with blood tests and ultrasounds in order to be sure it is progressing normally.