EFFECTS OF AGING ON MENSTRUAL-CYCLE HORMONES AND ENDOMETRIAL MATURATION

Objective: To investigate changes in menstrual cycle hormones and endometrial maturation that may contribute to the decline in fertility with aging. Design: Prospective controlled clinical study. Setting: Normal human volunteers in an academic research institution. Subjects: Women with regular menstrual cycles. Interventions: Thirty-two women, aged 20 to 30 or 40 to 50 years, had daily blood drawing starting on cycle day 6 to 10 and continuing until 2 days after the onset of next menses. In addition, 60 women, aged 20 to 30 or 40 to 50 years, had a total of 93 endometrial biopsies performed on day 7 to 9 after the LH surge. Main Outcome Measures: Serum LH, FSH, E(2), inhibin, P, and placental protein 14 (PP14) levels and histologic maturation of the endometrium. Results: Serum FSH levels were increased whereas inhibin concentrations were reduced in the luteal-follicular transition of women >40 years. No other hormonal changes were seen in this population, including P and PP14 secretion. Disruption of endometrial maturation occurred at a similar frequency in both age groups. Conclusions: Follicular recruitment, but not luteal function or endometrial maturation, is disturbed in cycling women >40 years and may contribute to the decline in fertility with aging.