Abnormal ovarian function sometimes causes incompletely developed follicles (ova) to accumulate in the ovaries. These ova fail to mature and ovulate, therefore causing them to accumulate as cysts in the ovary and contributing to infertility in the woman.

Polycystic ovaries are two to five times as large as normal ovaries, and they have a white, thick, very tough outer covering. This condition is commonly called Stein-Leventhal syndrome, and usually develops shortly after puberty.

A woman with polycystic ovaries will stop menstruating (she may not have ever started) or will menstruate erratically. She will gain weight, eventually becoming obese, and may develop excessive amounts of facial or body hair (hirsutism). Some women exhibit virilization.

Although the cause of Stein-Leventhal is not fully understood, there are several theories suggesting that problems with estrogen production and hypothalamic-ovarian feedback may be responsible.

Normal ovarian function is dependent on a number of hormones and failure of one or more of these hormones to be produced at the right time, in the proper concentration, can interfere with normal development.

Ovarian function will not proceed normally if a woman's body does not produce sufficient amounts of pituitary hormones. However, an increase in the amount of follicle-stimulating hormone (FSH), which is one of the hormones normally produced by the pituitary gland, is frequently successful in stimulating the underdeveloped ova to mature and be released from the ovary.

Women diagnosed with this disorder frequently have a mother or sister(s) with similar symptoms commonly associated with PCOS (polycystic ovarian syndrome). However, there is not currently enough evidence to prove a genetic link to the disease.

Conception is frequently possible with proper surgical or medical treatments. Following conception, pregnancy is normally uneventful.