The pregnancy hormone human Chorionic Gonadotropin (hCG) may be prescribed to ensure that an egg is actually released, that is to stimulate the actual ovulation. It can be administered to women whose follicles do not mature or whose ovulation does not occur during fertility treatment in order to better assess the moment of ovulation(s). There is therefore a difference between the hormones that ensure that the follicles grow - the ovulation stimulating medicines - and this hormone that is administered to stimulate the final maturation and the ovulation itself. hCG is often used in combination with the ovulation stimulating medicines. The hormone is prepared from the urine of pregnant women. An example of hCG is Pregnyl®.

hCG is administered as a one-off subcutaneous injection. When insemination is planned, the timing of the hCG injection is critical. Your doctor will indicate when you must administer the injection. For IVF, it is also of the utmost importance to administer the injection at the exact time that your specialist indicates, because the timing of the puncture is synchronised to this; the ova must be sufficiently matured, but cannot yet have ovulated.

• Local reaction where the injection takes place.
• Sometimes, allergic reactions.
• Rarely, general rashes and fever.
• In combination with ovulation stimulating medicines, overstimulation can occur.