Anovulation - disturbance of a menstrual cycle, at which there is no ovulation (break of a follicle of an ovary and emission of an ootid in an abdominal cavity), in an ovary is not formed a yellow body, the proliferative phase is not replaced secretory and in most cases there does not come a phase of a desquamation. The anovulation can be accompanied by an oligomenorrhea, an amenorrhea. Distinguish a physiological and pathological anovulation.

The physiological anovulation and amenorrhea are characteristic for pregnancy, the postnatal and lactational periods. To physiological carry also an anovulation in climacteric the periods. At healthy women of genital age with the kept genesial function menstrual cycles without an ovulation can be bound to short-term disturbance of function of system of a hypothalamus, a pituitary body and ovaries at stress, crossing to other climatic zone, etc.

Pathological anovulation. Pathological consider the chronic anovulation, accompanied as the sterility, caused by proof frustration of system of a regulation of a menstrual cycle at its various levels. To the primary reasons of a chronic anovulation carry a dysgenesis of gonads; defects of ferment systems of the ovaries participating in a folliculogenesis; autoimmune lesions of ovaries; a lesion of a tissue of ovaries at radial and chemotherapies; a syndrome of an attrition of ovaries, or a syndrome of refractory ovaries. One of principal causes of an anovulation - frustration of a hypothalamus and a pituitary body, secretions accompanied by disturbance by a pituitary body of the gonadotrophic hormones adjusting a folliculogenesis and an ovulation, at a normal level of Prolactinum in a blood.