Polycystic ovaries, as defined by the 2003 Rotterdam consensus criteria, are found to be very common in young healthy women.

Background: The criteria for polycystic ovaries (PCO) as defined by the 2003 Rotterdam consensus are based on the follicle number and ovarian volume, which decrease with age. A study was performed to assess the influence of age on the PCO prevalence. In addition, the relation between follicle number and ovulation day was studied.

Methods: Assessments were done in a spontaneous menstrual cycle in 171 healthy volunteers. The ovulation day and cycle duration were recorded. Transvaginal ultrasonography was performed between cycle day 6 and 9 to determine the follicle number and ovarian volume.

Results: In the age groups between 18 and 22, 23 and 27, 28 and 32, 33 and 37, and 38 and 40 years, the prevalence of PCO was 83-84%, 66-84%, 42-79%, 19-33%, and 0-33%, respectively. Most PCO subjects had ovulatory cycles. The follicle number and ovarian volume decreased with age. There was a positive correlation between the follicle number and the ovulation day.

Conclusions: PCO were found to be very common in young women. The follicle number and ovarian volume decreased with age, and therefore also the PCO prevalence decreased with age. We believe the PCO criteria should be reconsidered and adapted to the woman's age. Ovulation occurred later with increasing follicle number.