Based on the knowledge of neuroendocrinous cycle control and the development of the pharmaceutical industry, the creation of preparations with endocrinous activity, which are a powerful tool in the medical practice of infertility treatment, became possible. The method and the consecutive order of applying these medicaments are called “Stimulation Protocol”. The purpose of their application is to form a sufficient number of mature follicles and to induce ovulation. The stimulation is controlled by means of ultrasound monitoring of the follicles growth and periodic assessment of some basic hormonal indicators. The application of stimulation protocols is the basic method of ovulation induction also in the in vitro fertilization (IVF) program.

These are applied for the purpose of preventing premature rise of endogenous LH, in response to the fast rising serum Е2 during the formation of a multitude of follicles. The analogues reduce the risk of spontaneous ovulation, as well as the possibility for continuation of the stimulation in cases with asynchronous follicles growth. On the other hand, the use of GnRH-analogues in the ovarian stimulation protocol provides an opportunity for creation of comfort both for the laboratory personnel and for the patents.

GnRH-agonist protocols:

There are three main protocols using GnRH-agonists in the controlled ovarian hyper stimulation. The most widely applied protocol is the so-called “long protocol”. With it the application of GnRH-agonists starts in the middle of the luteal phase of the previous cycle. Another protocol is the so-called “short protocol”, in which the application of GnRH-agonists and gonadotropines starts together in the early follicular phase of the stimulated cycle and ends with the application of human chorio gonadotopine (HCG). In the third one, the so-called “ultra short protocol”, GnRH-agonists are usually applied only in the course of three days in the beginning of the cycle stimulation.

GnRH-antagonist protocols:

which on the base of the GnRH antagonist application method divide into: multiple dosing Lubeck protocol (GnRH antagonist is included after day 6, with application of 0,25 mg/daily dose); a single dosing French protocol (GnRH antagonist is included on day 8-9, with single application of a 3 mg dose).

Other protocols

For the purpose of individual approach to treatment and achievement of maximum ovarian response to СОН, it is sometimes necessary to apply specific protocols. The following modified protocols are possible:

• Combination of СС with gonadotropines;


• Combination of aromatasa inhibitors with gonadotropines – the aromatasa inhibitors improve the ovarian response and the embryos quality in cases of unsatisfactory ovarian response;


• Other alternative protocols – in some cases, for the purpose of attaining optimal ovarian response in the main protocols are included such medicaments as: bromocriptine, growth factors and low doses of aspirin.