How is IVF Performed?

A single attempt to achieve a pregnancy with IVF is called a cycle and includes several steps. The first is hormonal control of the woman's menstrual cycle, next comes stimulation of her ovaries with fertility drugs followed by close monitoring of the growth of the ovarian follicles, then egg retrieval and, lastly, transfer of a number of fertilized eggs (embryos) into her uterus.

Menstrual Cycle Control: The first step here is the use of birth control pills ("BCPs"), a seemingly odd thing for a fertility program to prescribe. The pills are started on the day a period starts or on the very next day and continued for 10-35 days until Lupron, a medicine that keeps the pituitary gland at rest, can be started. The length of time on BCPs is determined by when the period starts in relation to the week that is scheduled for the egg retrieval and embryo transfer. Since that is the busiest week of the entire IVF process it is important to select it with care.

Stimulation of Follicular Development: Once the Lupron is started and the BCPs finished a menstrual period will begin. A few days later we do a vaginal ultrasound exam in the office to make sure the pituitary gland has been successfully suppressed and that the ovaries and endometrium are ready for stimulation. Usually the ultrasound indicates normal baseline results and we can begin the next step, the use of the fertility drugs. The brand names of these preparations of FSH (Follicle Stimulating Hormone) are rather numerous: Follistim, Gonal-F, Repronex, Humagon, Metrodin, Fertinex and Pergonal. Most commonly a combination of two of these medications are used in the form of a daily injection for 7-10 days. It has long been our custom to teach a spouse, relative, friend or neighbor to give injections so frequent trips to our office are not needed.

Monitoring the Cycle: Usually we check for follicle growth after 5-7 days of the fertility drug injections. This involves a blood test to measure estradiol and a vaginal ultrasound to count and measure the follicles. Few women have follicles big enough to discontinue the medications at this point. Most must continue the injections and return for another blood test and ultrasound in 1-3 days.

Eventually the lead follicles reach a critical size and we can stop the fertility drugs. Now we must give an injection of HCG (Human Chorionic Gonadotropin) which will serve the same function as a natural cycle's LH surge. That includes final growth of the follicles, maturation of the eggs within the follicles and weakening of the follicle wall in preparation for ovulation. The biggest follicles will begin rupturing and releasing their eggs 39-40 hours after the HCG injection.

Egg Retrieval: The egg retrieval (ER) is scheduled to take place 36 hours after the HCG injection and is a procedure done in our office under light anesthesia (actually intravenous sedation) administered by an anesthesiologist. A needle guided by ultrasound is used to pass through the top wall of the vagina and into the fluid filled egg sacs (follicles) in the ovary. This may sound complex but is actually quite easy and causes no pain, thanks to the anesthesia. It takes about 15 minutes to gather the eggs and the patient is ready to go home 60-90 minutes later. The fluid we remove from the follicles is given immediately to our embryologists who use their microscopes to find the otherwise invisible eggs.

Embryo Transfer: The eggs are usually inseminated a few hours after retrieval with sperm from the husband. This is done by our embryologists who are also responsible for culturing the fertilized eggs (now called embryos) until the time of transfer to the wife's uterus. The embryo transfer is usually done 3 days after the egg retrieval when the embryos are at the 4-10-cell stage. In selected cases transfer is done at the 5-day point when the embryos are 'blastocysts'. The transfer is a very simple procedure and is nearly always completely painless. It is very much like a routine pelvic exam and involves the passage of a very small plastic catheter through the cervix. A tiny drop (20-30 microliters) of culture media with the microscopic embryos suspended within is deposited in the upper reaches of the uterus.

Embryo Freezing (Cryopreservation): Embryos that are not transferred can be frozen in liquid nitrogen provided they are of good quality. Once frozen they can remain potentially viable for many years, perhaps even a decade. And as amazing as it may seem babies produced by frozen embryo transfer are just as healthy and have exactly the same chance of having birth defects as do babies conceived naturally.