Does ovarian follicle depletion cause low estradiol and progesterone with high FSH and LH in menopause?

The transition into menopause is characterized by a fundamental shift in the hypothalamic-pituitary-ovarian (HPO) axis, driven primarily by the exhaustion of the ovarian reserve. This process results in a predictable hormonal profile defined by low circulating steroids and significantly elevated gonadotropins.

Clinical effectiveness and hormone profiles

The depletion of the primordial follicle pool is the established physiological cause of the hormonal changes that define menopause. Clinical longitudinal data, such as the Study of Women's Health Across the Nation (SWAN), show that as follicles are lost, the ovaries' capacity for steroidogenesis declines sharply.

• Estradiol and Progesterone: Postmenopausal women typically exhibit serum estradiol levels below 30 pg/mL. The absence of ovulation means the corpus luteum does not form, leading to a persistent state of low progesterone.
• Gonadotropins (FSH and LH): In response to low ovarian output, the pituitary gland increases secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH levels typically rise above 30–40 mIU/mL, and often reach ranges of 30–120 mIU/mL, while LH also increases significantly (20–70 mIU/mL).

Mechanistic explanations

The endocrine hallmark of menopause is "hypergonadotropic hypogonadism," which occurs through a disruption of the negative feedback loop.

• Feedback Loss: Under reproductive conditions, maturing follicles produce estradiol and inhibin B. These hormones provide negative feedback to the hypothalamus and pituitary, suppressing GnRH and FSH secretion.
• The FSH Rise: As the follicle count drops, inhibin B levels fall first, removing the primary "brake" on FSH. This is why FSH often rises before a significant drop in estradiol is observed in early perimenopause.
• Cellular Depletion: The loss of granulosa cells within the follicles results in the downregulation of key enzymes like aromatase (CYP19A1). Without these cells and enzymes, the ovary cannot convert cholesterol into estradiol, even when stimulated by high levels of FSH.

Bottom line

The claim is fully supported by established medical science. The depletion of ovarian follicles removes the negative feedback provided by estradiol and inhibin B, resulting in the characteristic menopausal profile of persistently low estradiol and progesterone accompanied by high levels of FSH and LH.