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 >40years. 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 >40years and may contribute to the decline in fertility with aging.