Menopause and Postmenopausal Hormone Therapy¶
Chapter 407 | Part 12: Endocrinology and Metabolism
KEY CLINICAL POINTS¶
- Menopause is defined as the permanent cessation of menstruation due to ovarian follicular decline, diagnosed after 12 months of amenorrhea with an average age of 51 years.
- STRAW+10 classification stages menopause based on menstrual cycle changes, hormone levels (FSH, AMH, inhibin B), and symptoms, with perimenopause preceding menopause by 2–8 years.
- Postmenopausal hormone therapy (HT) has mixed benefits and risks, including reduced fracture risk and increased breast cancer risk, with significant age-dependent effects.
1. DEFINITION & OVERVIEW¶
Menopause marks the end of reproductive function due to ovarian follicular loss. Perimenopause precedes menopause by 2–8 years, characterized by irregular cycles and hormonal fluctuations. The STRAW+10 classification system categorizes reproductive aging stages based on menstrual patterns, hormone levels, and symptoms.
STRAW+10 Staging System¶
| Stage | Terminology | Duration | Principal Criteria | Supportive Criteria | Descriptive Characteristics |
|---|---|---|---|---|---|
| –5 | Reproductive | Variable | Menstrual cycle variable to regular | FSH low, AMH low, Inhibin B low | Symptoms: Vasomotor symptoms |
| –4 | Peak | Variable | Regular menstrual cycle | FSH low, AMH low, Inhibin B low | Symptoms: Vasomotor symptoms |
| –3b | Late | Variable | Regular menstrual cycle | FSH low, AMH low, Inhibin B low | Symptoms: Vasomotor symptoms |
| –3a | Perimenopause | 1–3 years | Subtle changes in flow/length | FSH variable, AMH low, Inhibin B low | Symptoms: Vasomotor symptoms |
| –2 | Early Menopause | 2 years | Interval of amenorrhea ‡60 days | FSH >25 IU/L, AMH low | Symptoms: Vasomotor symptoms |
| –1 | Late Menopause | 3–6 years | Stabilizes FSH, AMH very low | FSH stabilizes, AMH very low | Symptoms: Increasing urogenital atrophy |
| Stage | Terminology | Duration | Principal Criteria | Supportive Criteria | Descriptive Characteristics |
|---|---|---|---|---|---|
| +1a | Postmenopause | Remaining lifespan | No menstrual cycle | FSH stabilizes, AMH very low | Symptoms: Increasing urogenital atrophy |
1.1 Stages of Reproductive Aging (STRAW+10)¶
The STRAW+10 system defines stages from early reproductive years to postmenopause, using menstrual cycle changes, hormone levels (FSH, AMH, inhibin B), and symptoms. Perimenopause (Stage –3b to +1c) is marked by irregular cycles and fluctuating hormone levels.
1.2 Hormonal Changes¶
During menopause, FSH levels rise sharply while estradiol declines. Anti-Müllerian hormone (AMH) and inhibin B also decrease, reflecting ovarian reserve depletion. Estrone levels remain relatively preserved due to adrenal androgen conversion.
2. EPIDEMIOLOGY¶
Menopause occurs at an average age of 51 years in the U.S. Perimenopause lasts 4 years on average, with smoking accelerating the transition by 2 years. Risk factors include age, smoking, and family history. Osteoporosis and cardiovascular disease risks increase postmenopause.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
Menopause results from ovarian follicular depletion, with FSH and estradiol levels fluctuating during perimenopause. Hormonal changes lead to vasomotor symptoms, urogenital atrophy, and metabolic shifts. The STRAW+10 system reflects the interplay between hormonal and symptomatic changes.
4. CLINICAL FEATURES¶
Common symptoms include vasomotor symptoms (hot flashes, night sweats), vaginal dryness, and irregular bleeding. Perimenopause may also present with increased endometrial hyperplasia risk. Quality of life is significantly impacted by symptom severity and duration.
5. DIFFERENTIAL DIAGNOSIS¶
Symptoms of menopause must be differentiated from other age-related conditions (e.g., thyroid dysfunction, depression, cardiovascular disease). Hormonal changes during perimenopause can mimic other endocrine disorders.
6. INVESTIGATIONS & DIAGNOSIS¶
Diagnosis relies on menstrual history and hormonal assays (FSH >25 IU/L, estradiol <25 pg/mL). Transvaginal ultrasound and endometrial biopsy are used to rule out structural abnormalities. The STRAW+10 system guides staging.
7. MANAGEMENT & TREATMENT¶
Low-dose combined oral contraceptives are first-line for perimenopausal symptoms. Postmenopausal HT (estrogen-progestin or estrogen alone) may alleviate vasomotor symptoms but carries risks of breast cancer, stroke, and thrombosis. Non-hormonal alternatives include SSRIs, SNRIs, and vaginal estrogen.
Benefits and Risks of Postmenopausal Hormone Therapy (WHI Trial)¶
| Outcome | Estrogen-Progestin | Estrogen Alone |
|---|---|---|
| Symptoms of Menopause | fl65–90% risk | fl65–90% risk |
| Osteoporosis | fl33% fracture risk | fl33% fracture risk |
| Breast Cancer | ›24% risk | ›21% risk |
| Stroke | ›37% risk | ›35% risk |
| Colorectal Cancer | fl38% risk | No significant change |
| Type 2 Diabetes | fl19% risk | fl14% risk |
| Dementia (‡65) | ›101% risk | ›47% risk |
7.1 Perimenopausal Therapy¶
Low-dose combined oral contraceptives (e.g., 20 µ g ethinyl estradiol + 1 mg norethindrone) are effective for irregular bleeding and vasomotor symptoms. Progestin-only formulations may be used in smokers or women with cardiovascular risk.
7.2 Postmenopausal Hormone Therapy¶
Estrogen-progestin therapy reduces fracture risk but increases breast cancer and stroke risk. Estrogen alone may benefit bone density but carries endometrial cancer risk. Transdermal formulations may reduce thrombotic risk.
8. PROGNOSIS & COMPLICATIONS¶
HT use is associated with both cardiovascular benefits (e.g., reduced coronary events in younger women) and risks (e.g., increased stroke and breast cancer risk). Long-term use may increase osteoporosis risk, while discontinuation leads to gradual reversal of benefits.
9. SPECIAL CONSIDERATIONS¶
HT is contraindicated in women with a history of breast cancer, thrombosis, or liver disease. Smoking increases cardiovascular risks. Women aged <60 with menopause onset <10 years may benefit from short-term HT, while older women face higher risks.
10. KEY POINTS & CLINICAL PEARLS¶
- Menopause is diagnosed after 12 months of amenorrhea with average age 51 years. 2. STRAW+10 staging guides ovarian aging assessment. 3. HT benefits include fracture risk reduction but carry risks of breast cancer and stroke. 4. Non-hormonal alternatives (SSRIs, vaginal estrogen) are preferred for vasomotor symptoms. 5. HT should be individualized based on age, risk factors, and symptom severity.