Frequent occurrence of multiovular follicles and multinuclear oocytes in the adult human ovary.

A study of 117 ovaries of adult women showed that multiovular follicles and multinuclear oocytes are found in 98% of 18- to 52-year-old women. The relative frequency of these follicles was not age-dependent and varied between 0.06% and 2.44% of the total follicular population of the ovary. Their frequency was unaffected by gonadotropic hormones, oral contraceptives, pregnancy, or day of the menstrual cycle. Young women with benign cystic teratomas did not have more multinuclear oocytes and multiovular follicles than did other patients. The probability that such follicles will ovulate is very low; therefore they could not be a significant cause of the birth of dizygotic twins or the appearance of triploidy.