Laboratory Testing for Perimenopause
The core laboratory evaluation for a woman in perimenopause should include FSH, LH, estradiol, and prolactin, with TSH added if thyroid dysfunction is suspected, though perimenopause remains primarily a clinical diagnosis based on symptoms and menstrual pattern changes. 1
Essential Hormone Panel
The following tests constitute the recommended baseline evaluation:
- FSH (Follicle-Stimulating Hormone): This is the primary marker, as FSH rises progressively during perimenopause due to declining inhibin B secretion from the ovaries 1, 2
- LH (Luteinizing Hormone): Recommended as part of the core evaluation for determining menopausal status 1
- Estradiol: Useful for assessing ovarian function, particularly when obtained serially in women with irregular bleeding, though levels fluctuate widely during perimenopause 1, 2
- Prolactin: Included in the standard workup to exclude hyperprolactinemia as an alternative cause of menstrual irregularity 1
Critical Caveat About Hormone Testing
Single hormone measurements provide little useful information during perimenopause due to extreme hormonal fluctuations. 2 The clinical history—specifically menstrual pattern changes and vasomotor symptoms—remains the most appropriate method for assessing menopausal status 2. Laboratory testing is most valuable when menopausal status is uncertain, symptoms are severe or atypical, or you need to determine if ovarian function has returned after amenorrhea 1.
Thyroid Function Assessment
TSH and thyroid antibodies (TPO-Ab) should be checked liberally in perimenopausal women, as thyroid disorders commonly mimic menopausal symptoms and occur frequently in this age group. 1, 3
The rationale for broad thyroid screening includes:
- Hyperthyroidism and menopause share overlapping symptoms (hot flashes, palpitations, mood changes) 3
- Decreased TSH levels occur in 8-10% of women in their fifth and sixth decades 3
- Thyroid dysfunction exacerbates cardiovascular and bone density risks already elevated by estrogen depletion 3, 4
- Clinical manifestations of thyroid disease become less obvious with advancing age, making diagnosis more difficult 3, 4
Metabolic Screening
Fasting glucose or 2-hour oral glucose tolerance test should be obtained if insulin resistance is suspected, as metabolic changes accelerate during the menopausal transition. 1 This addresses the increased predisposition to diabetes that occurs with declining estrogen 5.
Cardiovascular and Bone Health Screening
While not hormone tests per se, the following are critical for comprehensive perimenopause evaluation:
- Fasting lipid profile: Should be checked every 6-12 months, as cardiovascular disease risk accelerates with estrogen decline 6, 5
- Bone densitometry (DXA): Baseline examination recommended in postmenopausal women aged 65 years and in younger postmenopausal women with one or more risk factors for premature bone loss 6
Cancer Screening Considerations
Women entering perimenopause must be counseled about endometrial cancer risks and instructed to report any unexpected vaginal bleeding or spotting immediately. 1, 6 This is particularly critical for women on selective estrogen receptor modulators (SERMs) like tamoxifen, who require annual gynecologic assessment 6.
Practical Algorithm for Testing
Order FSH, LH, estradiol, prolactin, and TSH as the initial panel for any woman aged 40-55 with menstrual irregularity or menopausal symptoms. 1 Add fasting glucose and lipid profile to assess metabolic and cardiovascular risk 6, 1. If TSH is abnormal, obtain thyroid antibodies 1. Remember that normal hormone levels do not exclude perimenopause—the diagnosis is clinical 2.
The annual health examination should include comprehensive screening for physical and psychological problems with appropriate lifestyle counseling 7. Avoid unnecessary repeat hormone testing, as fluctuations are expected and do not guide management 2.