Ovarian stimulation in the course of in vitro fertilization treatment is the procedure of choice. It ensures the optimal chance of pregnancy. Its aim is to prompt ovaries to the production of ovarian follicles containing egg cells. Usually, between several to less than twenty ovarian follicles are produced as a result of stimulation. The success of the IVF procedure depends mainly on the fact whether it was possible to obtain simultaneously a larger number of follicles, followed by mature egg cells.
During stimulation, a woman initially takes gonadoliberin/hypothalamic hormone analogues (e.g. Gonapeptyl, Decapeptyl, Diphereline, Synarel) or gonadoliberin antagonists (e.g. Cetrotide) which inhibit the function of the pituitary gland and the patients’ own hormonal function.
Next, gonadotropins are added (e.g. Menopur, Puregon, Gonal F, Fostimon, Merional), i.e. the medications which cause the growth of ovarian follicles.
The medications are administered in the form of subcutaneous or intramuscular injections; Puregon, Gonal F, Menopur are available in the form of pens with full regulation of the dose of administered medication.
Self-administration strictly requires the patient’s prior training carried out by a nurse or a midwife.
During stimulation, a woman takes the chosen hormone drugs (typically, as subcutaneous or intramuscular injections). The posology is adjusted by the treating physician and depends on the patient’s ovarian response. During the hormonal stimulation, the doctor monitors its course: typically, there are 1 to 4 consultations. The reaction of the ovaries to the administered medications (the growth of ovulatory follicles) is monitored by means of laboratory tests (determination of the serum estradiol levels) and/or by ultrasound examination, with the assessment of the number and size of the follicles (in vaginal ultrasound).
Having confirmed the presence of the follicles with appropriate size (over 17 mm) and the serum estradiol level corresponding to the number of follicles (this usually takes place after 7 to 14 days from gonadotropin administration), the patient is given hCG (e.g. Pregnyl, Choragon – intramuscularly or Ovitrelle – subcutaneously) in order to imitate the ovulatory peak, i.e. to induce ovulation or release of egg cells.
Alternatively, in the cycles with a GnRH antagonist, the ovulatory peak may be induced with a GnRH agonist.
After 34-38 hours from the administration of hCG or an agonist, the puncture of follicles and ovum pick-up are carried out.
In ovarian stimulation, the following stimulation protocols are used: protocols with GnRH agonists: short and long, and protocols with GnRH antagonists.
In each protocol, gonadotropins and agonists are taken every day at the same time (e.g. in the morning), each medication in a separate injection (this applies also when simultaneous use of different gonadotropins was ordered) and at different sites on abdomen or forearm. From the beginning of gonadotropin treatment, the patient should not take any preparations of acetylsalicylic acid (aspirin) as they cause the increased risk of bleeding after the ovarian puncture, unless the doctor decides otherwise.
There is currently no conclusive evidence confirming a higher efficacy of one type of stimulation protocol in all women qualified for the in vitro fertilization treatment. A stimulation protocol is chosen on a case-by-case basis.
The medications used during stimulation should be chosen in accordance with the selected stimulation protocol and the experience of the treating physician.