Ovulation Induction - Final Maturation and Release

Final Maturation and Release

Ovulation induction can also refer to the induction of the final maturation of already relatively developed ovarian follicles and their oocytes, as well as triggering oocyte release from the ovary. Colloquially, this is known as the "trigger shot." This induction of final maturation and release of oocytes is the physiological role the LH surge by luteinizing hormone.

Administration of medication for triggering of oocyte release avails for sexual intercourse or intrauterine insemination to be scheduled at ovulation, the most likely time to achieve pregnancy. In in vitro fertilization, induction of final maturation avails for egg retrieval when the eggs are fully mature.

Medications used for final maturation and/or release of oocytes include:

• A low dose of human chorionic gonadotropin (HCG or hCG), which may be injected after completed ovarian stimulation. Ovulation will occur between 38 and 40 hours after a single HCG injection. It is also used in in vitro fertilization, where it makes the follicles perform their final maturation. A transvaginal oocyte retrieval is then performed at a time usually between 34 and 36 hours after hCG injection, that is, just prior to when the follicles would rupture. HCG injection confers a risk of ovarian hyperstimulation syndrome.
• Induction of final maturation and/or release with a GnRH agonist is a valid alternative to HCG, resulting in an elimination of the risk of ovarian hyperstimulation syndrome. In in vitro fertilization, the delivery rate is approximately 6% less than with hCG triggering.