• * The center of assisted medical procreation of the CHU St Pierre is specialised in reproductive medicine. Reference center: quality label ISO 9001 obtained in 2008 and accredited by the AFMPS (Agence Fédérale des Médicaments et Produits de Santé).

Stimulation in in vitro fertilization

The aim of stimulating the ovaries in IVF is to ensure the simultaneous development of several follicles instead of just one in order to be able to collect several oocytes and to thus obtain several embryos so that at least one of them with a good morphology can be transferred.


There are 3 phases in stimulation:

  1. actual ovarian stimulation: hormone treatment using daily subcutaneous injections of gonadotropins (hMG: Menopur® or recombinant FSH: Puregon® or Gonal®F) ensures follicle growth. A long-acting gonadotropin was also recently introduced: corifollitropin alfa (Elonva®)replacing 7 days of daily injections.
    Stimulation is supervised through “monitoring” which consists of carrying out ultrasound scans and hormone tests on a very regular basis in order to monitor follicle growth.
  2. hypophysary inhibition: this consists of blocking hypophysis in order to prevent premature ovulation during ovarian stimulation. This inhibition can be achieved with 2 types of molecule: GnRH agonists or GnRH antagonists.
    GnRH agonists are given at the beginning of the cycle or at the end of the cycle preceding IVF. They can be administered in the form of a nasal spray (Suprefact®), as a single intramuscular injection (Decapeptyl® 3.75 mg) or as a daily subcutaneous injection (Decapeptyl® 0.1 mg or Gonapeptyl®).
    GnRH antagonists (Orgalutran® or Cetrotide®) are administered during ovarian stimulation according to highly specific criteria.
  3. triggering ovulation: this occurs when the follicles have reached maturity. It consists of an hCG injection (Pregnyl or Ovitrelle). This injection must be carried out at an exact time so that oocyte retrieval can take place 34 to 36 hours later.





Plan du site CHU Saint Pierre - Bâtiment 200, 5è étage . Département de Gynécologie-Obstétrique

Centre de Fécondation In vitro - 322, Rue Haute - Bruxelles Tel +32(0)2 535 3406 Fax +32(0)2 535 3409