Ovarian Stimulation For IVF
Why Is It Necessary To Stimulate Egg Production?
IVF, in vitro fertilization, is the process whereby follicles and eggs from a woman's ovaries are stimulated to develop and then the mature eggs are removed from the ovaries and fertilized outside of the uterus, in a lab. Once fertilized, they are transferred back to the uterus where, if successful, one or more of the embryos implant and grow. In order to improve the chances of success, it is important to have at least 8 to 15 eggs in the retrieval procedure.
A variety of ovarian stimulation medications is available to increase the number of follicles and eggs in the ovaries. During the regular menstrual cycle, only one follicle and one mature egg are produced, so stimulation is necessary to ensure an adequate number of follicles and eggs for the IVF procedure. All of the medications commonly used in IVF regimens involve injections of follicle stimulating hormone (FSH). These hormones are also referred to as gonadotropins or Human Menopausal Gonadotropins (HMG).
The Three Most Commonly Used Protocols For Ovarian Stimulation
There are three protocols most commonly used in IVF treatments. Luteal Lupron protocols, also called "down regulation" or "mid-luteal Lupron" protocols are the most commonly used in the US and many IVF specialists believe that there are better success rates using this protocol. Lupron works by affecting the pituitary gland's ability to produce the LH (luteal hormone) surge. Antagonist protocols involve the use of gonadotropin releasing hormone (GnRH) antagonist medications. Just as Lupron prevents a woman from having an LH surge, antagonist medications do the same thing, only differently. These medications work by competing with GnRH molecules already present in the body at the binding site in the pituitary gland. Flare and micro-flare protocols are used in situations where the woman has a low response to ovarian stimulation. This group would include advanced maternal age, women with high levels of FSH or indications of a low reserve of ovaries. The specialist will use the same types of medications as in luteal Lupron protocols, adjusting start days and dosages as needed.
The Drugs And Their Purpose
The three types of drugs commonly used in IVF stimulation protocols include a medication to suppress the LH surge until the follicles are mature. The drugs used for this are GnRH-agonist or GnRH-antagonist types of medication. Additionally, a FSH product is used to stimulate the development of multiple follicles and finally human chorionic gonadotropin (HCG) is administered to move the eggs into final maturation. It is necessary to administer injections FSH medications for 8 to 12 days to ensure the development of mature size follicles.
The goal of ovarian stimulation is to produce between 8 and 15 follicles that will produce quality eggs for retrieval. These eggs are used in the IVF treatment. While IVF can be effective with a low number of eggs, the success rates are far better when a larger number of eggs are recovered.