Serum luteinizing hormone profile during the menstrual cycle in polycystic ovarian syndrome.

Thirty-three patients with PCO were studied, focusing on the serum LH profile appearing during their menstrual cycles. The elevated LH level declined gradually after ovulation to the normal or near-normal range at the end of the luteal phase and the early follicular phase. The once declined LH level gradually elevated again with the increasing days from the beginning of menstrual flow and remained at a high level until the next ovulation. The LH response to LH-RH increased with the elevating basal LH level. These results may suggest that the timing of hormonal analysis is important for correct diagnosis of PCO.