HYPOTHALAMIC-PITUITARY AGING - PROGRESSIVE INCREASE IN FSH AND LH CONCENTRATIONS THROUGHOUT THE REPRODUCTIVE LIFE IN REGULARLY MENSTRUATINGWOMEN

OBJECTIVE Reproductive ageing is associated with reduced fertility and endocrine changes that become more pronounced during the perimenopaus al period. We aimed to assess changes in gonadotrophin concentrations and the onset of these changes during the reproductive life prior to t he perimenopause. SUBJECTS Ovarian and pituitary hormones were measure d and follicle growth monitored in 500 regularly cycling infertile wom en aged 20-44 years. MEASUREMENTS Serum levels of FSH and LH were dete rmined during the follicular phase and ultrasonography was used to mon itor follicle growth and ovulation. The luteal phase was assessed by s alivary progesterone measurements. Changes in basal FSH and LH with ag e during ovulatory cycles were assessed. RESULTS There was a significa nt progressive increase in FSH levels as early as age 29-30 years whic h was continued throughout the 30s and became more marked in the early 40s. LH levels showed significant increase at the age of 35-36 years which was maintained tilt the age of 40 years and followed by a furthe r increase in women aged >40 years. CONCLUSION An increase in FSH and LH concentrations can be detected in women with regular ovulatory cycl es quite early during the reproductive life. The increase in basal FSH (and later LH) may represent the earliest endocrine marker of reprodu ctive ageing. These age-related increases in FSH and LH can be used as hormonal markers to counsel patients as to the likelihood of their re productive potential.