This represents the beginning of the proceeding itself. The aim of this first phase, which lasts an average of 10 days, is to apply the appropriate medicines (primarily hormone injections) stimulating ovaries to develop an optimal number of follicles and the optimum number of egg cells.

Doctor that conducts the procedure, based on the findings of the woman, chooses a scheme of stimulation which is expected to give the best result. There are numerous protocols, the most famous being long scheme with a GnRH agonist and GnRH brief scheme with antagonists, as well as numerous modified protocols of stimulation with a mild stimulation or even carrying out the procedure in the spontaneous cycle, without hormonal stimulation.

It should be noted that there is no single recipe for all couples, but every couple deserves a scheme designed especially for them, based on their characteristics.

Although the procedures with mild stimulation are sometimes the best option and are very popular with patients, it should be noted that in most cases the rule is that the more of egg cells the greater the chance for success, and that is obtained only by classical or conventional stimulation with the use of hormonal stimulation.

Further course of this phase involves serial examinations of patients, starting from the fifth day of the therapy (usually every 2 days) where ovarian response is estimated on the basis of ultrasound exams and hormonal analysis. If necessary, treatment is adjusted, and the final moment to give – stop dose which causes the end maturation of egg cells is determined. This moment is estimated by the physician conducting the procedure based on a number of parameters. Normally it takes 3-4 reviews during stimulation.

Unfortunately, at this stage there is an option of suspension of the cycle unless there is an adequate response, and that the new stimulation starts, usually at a different protocol in one of the next cycle.