Ovulation Induction (OI) is a treatment option used to induce ovulation in women. Ovulation Induction is often called controlled ovarian hyperstimulation (OHS) and involves stimulating the ovaries with medication to begin to grow eggs.
Ovulation induction starts with the woman taking fertility medication such as FSH injections. These medications help stimulate the follicles by triggering the body to produce more FSH (follicle stimulating hormone) so that eggs can begin to grow within the ovaries. The growth of the egg containing follicles are monitored with a series of ultrasounds until the follicles reach their mature size. Typically a series of between 3-5 ultrasounds are needed in order to closely monitor the growth of the follicles to determine when they are mature and ready.
The desired size of the mature follicles should be around eighteen to twenty two millimeters in size before a trigger injection of HCG (human chorionic gonadotropin) is given to induce ovulation. Ovulation will then occur around thirty six hours after the injection is given. Typically ovulation induction is followed by either intercourse or insemination around the time that ovulation is scheduled to occur.
Controlled Ovarian Hyperstimulation is also a term used to describe the ovulation induction portion of In-Vitro Fertilization treatment. The woman is monitored with several ultrasounds to check the growth of her follicles while taking daily injections of follicle stimulating hormone. With IVF treatment, women are taking a large dose of FSH so blood testing is also performed during treatment to check the level of estradiol (or estrogen) in her bloodstream. Is it crucial that the blood levels remain stable and do not become too high or ovarian hyperstimulation syndrome can result. This is rare due to the careful monitoring that is used during the ovulation induction cycle. Once the follicles are mature and the injection of HCG is given, the egg retrieval procure is scheduled to extract the mature eggs from the ovaries before the follicles rupture and the eggs are released. The eggs are then mixed with sperm outside the body and fertilization occurs. This process is called In-Vitro Fertilization or (IVF)
In addition, clomid and letrozole can be used for ovulation induction cycles however blood level testing is not needed with these medications.