What happens to FSH (Follicle-Stimulating Hormone) and LH (Luteinizing Hormone) levels during menopause?

FSH and LH Levels in Menopause

Hormonal Changes During Menopause

Both FSH and LH levels become markedly and persistently elevated during menopause, with FSH typically rising earlier and more dramatically than LH as ovarian follicular activity declines. 1

Physiological Mechanism

The hormonal changes during menopause result from:

• Profound decline in ovarian follicle numbers, which is the primary driver of the menopausal transition 1
• Decreased inhibin B secretion from declining small antral follicles, which removes negative feedback on the pituitary gland 1, 2
• Loss of estradiol production by the ovary, further removing negative feedback on gonadotropin secretion 1
• Compensatory pituitary response with increased FSH and LH secretion attempting to stimulate remaining follicular activity 3

Specific Hormone Level Patterns

FSH elevation:

• FSH begins rising years before clinical menopause, particularly in the early follicular phase of menstrual cycles 1
• The rise accelerates after approximately age 43, with a significant increase occurring when women reach their mid-40s 4
• FSH reaches postmenopausal ranges (markedly elevated) after final menses 1, 5

LH elevation:

• LH levels remain relatively normal until later in the transition compared to FSH 6
• LH eventually rises to postmenopausal ranges, though typically less dramatically than FSH 5
• During perimenopause, isolated LH elevation (without FSH elevation) can occur transiently 5

Estradiol changes:

• Estradiol levels remain relatively preserved or may even rise during early-to-mid transition due to elevated FSH stimulation 1, 2
• Estradiol falls profoundly only in late perimenopause and after menopause 1

Clinical Diagnostic Considerations

Important Caveats About Hormone Testing

Hormone levels during the menopausal transition are highly unreliable for determining menopausal status because:

• FSH and estradiol fluctuate markedly during perimenopause, varying widely between individuals and within the same individual over time 1, 2
• Both ovulatory cycles (with normal FSH) and anovulatory cycles (with elevated FSH) can occur intermittently even late in the transition 2
• Postmenopausal biochemical parameters do not guarantee permanent postmenopausal state, as ovulatory cycles can occur within 16 weeks of what appears to be final menses 5

When to Use FSH/LH Testing

For women under age 60:

• Menopause diagnosis requires amenorrhea for ≥12 months plus FSH and estradiol in postmenopausal ranges (elevated FSH with low estradiol) 7, 8
• Both FSH and estradiol should be measured concurrently, as FSH alone is insufficient 8

For women age 60 or older:

• No laboratory testing is required; age and amenorrhea are sufficient for diagnosis 7, 8

Special populations requiring testing:

• Women on tamoxifen or toremifene (FSH alone is unreliable in this group) 8
• Women with chemotherapy-induced amenorrhea (serial estradiol measurements are more useful than FSH) 8
• Women considering hormone replacement therapy who have amenorrhea <12 months 7

Clinical Pitfalls to Avoid

• Do not rely on single FSH measurements during perimenopause to determine menopausal status, as levels fluctuate dramatically 1, 2
• Do not assume elevated FSH means permanent menopause during the transition, as ovulatory cycles can resume 5, 2
• Do not use FSH testing in women on GnRH agonists/antagonists, as menopausal status cannot be determined while on these medications 8