Laurence A Cole1, Jovanna M Gutierrez. 1. USA hCG Reference Service, Department of Obstetrics and Gynecology, University of New Mexico, Albuquerque, NM 87131, USA. larry@hcglab.com
Abstract
OBJECTIVE: To present a comprehensive study of pituitary human chorionic gonadotropin (hCG) production during the menstrual cycle, investigating its occurrence, timing and the possibility of a separate biologic role for pituitary hCG during the normal menstrual cycle. STUDY DESIGN: Daily urine samples were tested from 185 women during 405 normal menstrual cycles. Levels of hCG and luteinizing hormone (LH) were measured daily. RESULTS: hCG levels were detected at LH peak in 84% of menstrual cycles. At this time, hCG levels paralleled LH values. The remaining menstrual cycles (16%) had significantly lower LH levels, suggesting lack of detection of hCG as a result of low concentration of LH or very dilute urines. We infer that hCG is produced in all menstrual cycles. CONCLUSION: hCG is seemingly produced alongside LH in all menstrual cycles. hCG has a much greater circulating half-life compared to LH. It may function to extend the short, sharp LH peak in promoting ovulation or in promoting initial progesterone production by the corpus luteal cells.
OBJECTIVE: To present a comprehensive study of pituitary human chorionic gonadotropin (hCG) production during the menstrual cycle, investigating its occurrence, timing and the possibility of a separate biologic role for pituitary hCG during the normal menstrual cycle. STUDY DESIGN: Daily urine samples were tested from 185 women during 405 normal menstrual cycles. Levels of hCG and luteinizing hormone (LH) were measured daily. RESULTS:hCG levels were detected at LH peak in 84% of menstrual cycles. At this time, hCG levels paralleled LH values. The remaining menstrual cycles (16%) had significantly lower LH levels, suggesting lack of detection of hCG as a result of low concentration of LH or very dilute urines. We infer that hCG is produced in all menstrual cycles. CONCLUSION:hCG is seemingly produced alongside LH in all menstrual cycles. hCG has a much greater circulating half-life compared to LH. It may function to extend the short, sharp LH peak in promoting ovulation or in promoting initial progesterone production by the corpus luteal cells.