What bloodwork is recommended to assess hormonal status in postmenopausal women, including Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), and estradiol levels?

Postmenopausal Hormone Testing

Primary Recommendation

For postmenopausal women, measure FSH and estradiol levels to confirm menopausal status if under age 60 with 12 months of amenorrhea; no laboratory testing is needed for women 60 years or older, as age alone confirms menopause. 1, 2

Hormones to Measure

Essential Tests

• FSH (Follicle-Stimulating Hormone): This is the primary marker, with postmenopausal women showing FSH levels elevated 13-18 times above premenopausal values, peaking 2-3 years after menopause 3
• Estradiol: Must be measured concurrently with FSH, as postmenopausal estradiol drops to approximately 20% of premenopausal levels (typically <25 pg/mL) 1, 3

Optional Tests (Clinically Indicated)

• LH (Luteinizing Hormone): May provide additional information about ovarian function, rising 3-fold initially and peaking at 3.4 times premenopausal values 1, 3
• Prolactin: Should be measured only when ruling out other causes of menstrual irregularity 1
• AMH (Anti-Müllerian Hormone): May assess ovarian reserve but has limited normative data in postmenopausal women 1

Age-Based Testing Algorithm

Women Under 60 Years

• Require both FSH and estradiol after 12 months of amenorrhea to confirm postmenopausal status 2
• Both values must be in the postmenopausal range (elevated FSH with low estradiol) 1
• The combination provides stronger diagnostic certainty than either hormone alone 2

Women 60 Years or Older

• No laboratory testing required - age alone is sufficient for clinical diagnosis 2
• This recommendation is consistent across major guidelines 2

Special Clinical Situations

Women on Tamoxifen or Toremifene

• FSH alone is unreliable in this population 2
• Must measure both FSH and plasma estradiol, with both in postmenopausal ranges required for diagnosis 1, 2
• Hormone levels and amenorrhea are unreliable indicators during tamoxifen treatment 1

Post-Chemotherapy Patients

• FSH is not reliable for determining menopausal status 2
• Serial estradiol measurements are more useful to assess return of ovarian function 1, 2
• Amenorrhea after chemotherapy does not reliably indicate menopause, as ovarian function may resume 1

Women on GnRH Agonists/Antagonists

• Cannot determine menopausal status while receiving these medications 1, 2
• Requires oophorectomy or serial hormone measurements after discontinuation for definitive status determination 2

Post-Hysterectomy with Intact Ovaries

• FSH and estradiol levels should be checked to determine menopausal status 1

Clinical Indications for Testing

Hormone testing should be performed when women present with:

• Irregular menstrual cycles 1
• Vasomotor symptoms (hot flashes, night sweats) 1
• Before initiating hormone therapy 1
• After chemotherapy to assess ovarian function 1

Important Caveats

Hormone Level Variability

• FSH can be elevated years before actual menopause - many premenopausal women aged 45-49 show hypergonadotropinemia while maintaining estradiol levels >25 pg/mL 4
• In perimenopausal women, FSH may range from 4-32 IU/g Cr compared to 3-7 IU/g Cr in younger women, with paradoxically elevated estrone levels 5
• Some ovarian estradiol secretion may persist even with elevated gonadotropins in early postmenopause 4

Serial Measurements

• For women on endocrine therapy or with chemotherapy history, consider serial measurements rather than single values 2
• Serial estradiol levels help determine if ovarian function has returned in amenorrheic women who develop bleeding 1

Correlation Limitations

• Serum FSH and estradiol levels show minimal negative correlation with each other and no correlation with age or years since menopause 6
• Clinical diagnosis should rely on menstrual history and age, not laboratory values alone, particularly in perimenopause 6