This is the process of using fertility medication to help a woman 'superovulate' or produce multiple mature eggs. For IVF, we like to obtain 10-20 total eggs, if possible. During this stage the patient will also receive regular ultrasounds and blood tests to measure estrogen levels and determine any ovarian cysts.
This exam will indicate whether there are any cysts on the ovaries. Many cysts go away on their own. If not, the doctor can aspirate or 'collapse' them so that treatment may proceed.
Estrogen level blood test
Estrogen is a primary female hormone produced by the ovary. During a non-IVF cycle, estrogen levels rise during ovulation. At the beginning of the cycle the estrogen or Estradiol level tells us that everything is quiet and ready to begin. During stimulation, whenever we perform an ultrasound, we will also perform Estradiol blood tests. The magnitude of the blood level can help us with dose adjustments early in stimulation. In the final days of stimulation, the magnitude of the level is not as important as making sure the level never takes a precipitous drop during stimulation. This would be a bad sign and indicate the eggs are unhealthy. Fortunately, Estradiol drops of this magnitude are rare.
Ovulation stimulating medications
After a woman begins her menstrual period, she will begin taking gonadotropin medications. This is a concentrated form of the body's natural ovulation-stimulating hormone that stimulates the growth of egg-containing sacs called follicles. Each follicle usually holds one egg. In a natural menstrual cycle, only one follicle will mature. In an IVF cycle, anywhere from two to 30 follicles may develop, although we are usually aiming for about 10-20 total eggs.
Gonadotropins have the names Gonal-F, or Follistim, Bravelle and Menopur. In patients that are on a protocol without Leuprolide, another medication called Ganirelix may be employed during the final 3-4 days of stimulation to prevent any kind of LH surge and thereby prevent ovulation prior to the egg retrieval.
For the vast majority of IVF patients, the number of days spent taking gonadotropin injections (the number of days "in cycle") is about 10-12 days. During this time, patients will have 4-5 monitoring visits which include ultrasound monitoring and Estradiol blood tests.
Preparing the eggs for ovulation and fertilization
At each monitoring visit, the patient's doctor will perform ultrasound exams and estrogen level tests to determine whether follicles are sufficiently large and eggs are mature. Once the majority of egg follicles measures between 16 and 20 mm on average diameter, they will be advised to stop taking Leuprolide or Ganirelix and gonadotropin medications and inject just one dose of a medication called human chorionic gonadotropin or hCG, which prompts the eggs to mature and detach from the follicle wall.
Timing of the hCG injection is critical
Because ovulation normally occurs about 40 hours after hCG injection, the egg retrieval will be scheduled approximately 36 hours after taking the medication. The patient will be asked to take the hCG injection at the exact time that they are instructed. We will walk them through this process well beforehand and be sure that they are comfortable with their instructions.