After detail examination of 24-year-old female patient (cariotype — 46XX/45XO, sex chromatin — 11 %, serum prolactin level — more than 200 mIU/ml (normal level — less than 26,72), ovarian ultrasound, geneticist consultation, magnetic resonance imaging of the hypophysis), the сlinical diagnosis was established: pituitary microadenoma. Hyperprolactinemic hypogonadism. Mosaic Turner syndrome. Genital infantilism. Infertility of endocrine origin. First menstruation occurred in 3 months, and pregnancy — in 4 month after initiation of the treatment with alactin 0.5 mg twice a week, after that bromocriptine 2.5 mg once a day was administered. On the 39–40th week of pregnancy, the patient gave birth to a girl (via cesarean section), whose weight was 3.4 kg and height — 48 cm.