In Vitro Fertilization (IVF) is based primarily on ovarian stimulation in order to produce more eggs than the one egg that would naturally be released by the woman during her natural menstrual cycle. In vitro fertilization can be achieved with a very low number of eggs, but the success rate rises significantly higher when more eggs are harvested.
With ovarian stimulation for IVF, the goal is to produce about 8 to 15 follicles that will provide quality eggs in the egg collection process. When a sufficient number of follicles (small cysts containing the ova) have reached an acceptable size, then the egg harvest is scheduled.
There are three (3) basic protocols for ovarian stimulation in IVF. The Agonist Long Protocol, the Agonist Short Protocol, and the Protocols of Antagonists.
- Agonist Long Protocol: It begins on the 2nd or the 21st day of the cycle, followed by the administration of certain drugs called GnRH-analogues, which are to be taken for 10-14 days and they are intended to prepare and suppress the ovaries by temporarily ceasing their function. A blood test for hormone control is then performed during menstruation. Then, along with the administering of the GnRH-analogue, the drug for inducing stimulation is started, which helps the ovaries produce many follicles.When more than 3 follicles are larger than 17mm, a chorionic gonadotrophin (Pregnyl or Ovitrelle) injection (night injection) is administered, which is essential for the final stage of maturation of the oocytes. The eggs are scheduled for harvesting 34 to 36 hours after the administering of chorionic gonadotrophin.
Agonist Short Protocol: It begins on the 2nd day of the ovulation suppression cycle (GnRH-analogues), and after one day of treatment, the ovarian stimulation drugs are also administered. Monitoring of proper follicular development is done by combining blood tests and vaginal ultrasounds, just as in the Agonist Long Protocol. The same applies to the final dose of chorionic gonadotrophin. Overall, this process lasts for about 8 to 14 days.
Antagonist Protocol: The Antagonist Protocol is the most recent of the three, and during this IVF method newer drugs called GnRH-antagonists (Cetrotide, Orgalutran) are administered. It starts on the 2nd day of the menstrual cycle with ovarian stimulatory drugs. After 5 to7 days, ovulation suppressants (GnRH antagonists) are also added. This treatment lasts for about 8 to 14 days.