Human chorionic gonadotropin (hCG) is available in two forms.  One is a powder derived from the urine of pregnant women which needs to be dissolved in sterile water, loaded into a syringe, and injected into a muscle (usually the buttocks).  The other (Ovidrel®) is a more expensive but more convenient product produced by recombinant technology, pre-packaged into a syringe for injection (subcutaneously=under the skin) with a short needle.

hCG in intra-uterine insemination (IUI) cycles:

hCG is used in some patients who are usually receiving other fertility drugs in order to “trigger” ovulation. The eggs are released from their follicles about 40 hours after the hCG injection. Artificial insemination will usually be scheduled for 36-44 hours after the hCG injection when a single insemination is planned, or at approximately 24 and 48 hours after the hCG injection when two inseminations are to be done.

hCG in IVF cycles:

Throughout an IVF cycle, gonadotropin fertility medications are injected daily for approximately ten days. The fertility medications cause the ovarian follicles, which are the grape-like structures that contain the egg, grow and secrete estrogen. The hormone concentrations in the blood are measured, and the follicle sizes in the ovary are monitored by ultrasound. When the follicles are the appropriate size, another gonadotropin product called human chorionic gonadotropin (hCG) is injected. hCG functions similarly to luteinizing hormone (LH). It initiates the three aspects of ovulation – maturation of the eggs, production of progesterone, and release of the eggs from the follicle 40 hours after the injection. The egg retrieval procedure for IVF is scheduled 36 to 38 hours after the injection, just before the eggs are released.