A comparative assessment of variations in sex hormone levels and echographic parameters of fertile and infertile cycles was carried out in patients with gonadotrophic deficiency during pergonal induction of the ovulation. It was demonstrated that 83% of the infertile cycles were the first stimulation cycles. Basic differences were identified in the variation of sex hormone levels and echographic parameters of target organs between the fertile and infertile cycles. It is concluded that the first ovulation-induction course should be regarded as a preventive or preparatory one, where an optimum drug dosage is adjusted while the gonads and target organs are getting ready for the ovulation.