How common are polycystic ovaries in normal women and what is their significance for the fertility of the population?

OBJECTIVE: We wished to determine the prevalence of polycystic ovaries (PCO) and relate morphological appearance to fertility. DESIGN: We sent postal invitations to a random sample of women born in the years 1952-1969 from a list of a single Group Practice to attend for reproductive history questionnaire, examination, ultrasound scan of the ovaries and hormone measurements within 5 days of the onset of menstruation. SUBJECTS: Of 1065 women potentially available for study, 571 (54%) replied of whom 353 (62%) agreed to participate. One hundred and ninety (18%) completed the study, 163 were deferred (57 because of current or very recent pregnancy, 106 because of inconvenience at time approached), and 18 additional women volunteered. MEASUREMENTS: Prevalence of polycystic ovaries, ovarian size and morphology, menstrual history, features of androgen excess, fertility status, serum hormone levels. RESULTS: The prevalence of PCO was 22% (41/190). PCO and non-PCO women were similar with respect to age, body mass index, oral contraceptive pill (OCP) usage, acne, and menstrual pattern but hirsutism (Ferriman and Gallwey score > 7) was significantly (P = 0.006) more frequent among PCO women. Proven prior fertility was the same in PCO (56%) and non-PCO (64%) women and an equal proportion in each group had not yet tested their fertility. Of those women with previously proven fertility, self-perceived difficulty in conception occurred in similar proportions of women with and without PCO. Unresolved primary or secondary infertility (2.5-4%) was similar in both groups. Ovarian volume (each ovary separately) was larger in women with PCO irrespective of current OCP usage. Serum levels of oestradiol and FSH were similar in PCO and non-PCO women, but LH was distributed around a higher median in PCO women. Median testosterone and androstenedione levels were the same in PCO and non-PCO women. CONCLUSIONS: The prevalence of polycystic ovarian morphology is high but, in this sample of women, was accompanied by minimal clinical manifestations and apparently no deleterious effects on earlier fertility. An isolated finding of polycystic ovaries may be a normal variation and should not necessarily imply altered fertility potential.