What hormone levels to check and their normal ranges in a perimenopausal woman with severe fatigue 12 weeks post-COVID (Coronavirus Disease 2019) infection?

Hormone Testing for Perimenopausal Women with Severe Fatigue Post-COVID

For perimenopausal women experiencing severe fatigue 12 weeks post-COVID infection, comprehensive thyroid function testing is essential, including TSH, free T3, free T4, and anti-thyroid antibodies, as COVID-19 can trigger thyroid dysfunction that may persist during long COVID. 1, 2

Primary Hormone Panel to Order

Thyroid Function Tests

• TSH (Thyroid Stimulating Hormone): Normal range: 0.4-4.0 mIU/L
  • Low TSH has been observed in up to 56% of COVID-19 patients 3
  • Both low TSH and low T3 have been associated with COVID-19 severity and may persist after acute infection 4, 5
• Free T3 (Triiodothyronine): Normal range: 2.3-4.2 pg/mL
  • Low T3 is common in post-COVID patients and correlates with systemic inflammation 4
• Free T4 (Thyroxine): Normal range: 0.8-1.8 ng/dL
• Anti-thyroid antibodies:
  • Anti-TPO (thyroid peroxidase): Normal: <35 IU/mL
  • Anti-thyroglobulin: Normal: <20 IU/mL
  • Incident anti-TPO positivity has been observed following COVID-19 6

Reproductive Hormone Panel

• FSH (Follicle Stimulating Hormone): Normal perimenopausal range: 25-135 mIU/mL
• Estradiol: Normal perimenopausal range: 30-400 pg/mL
• Progesterone: Normal range varies by menstrual cycle phase
  • Menstrual alterations are common in women with long COVID 1
  • COVID-19 may affect ovarian hormone production due to ACE2 receptors on ovarian tissue 1

Additional Testing

• Complete blood count: To evaluate for anemia or ongoing inflammation
• C-reactive protein: Normal: <10 mg/L (to assess inflammation)
• Ferritin: Normal: 11-307 ng/mL (for women)
• Kidney and liver function tests: To rule out organ dysfunction 1, 2

Interpretation and Clinical Context

1. Thyroid dysfunction patterns post-COVID:

   • Subclinical thyrotoxicosis (low TSH with normal T3/T4) may indicate thyroiditis 4
   • Low T3 syndrome (normal TSH with low T3) may represent non-thyroidal illness syndrome 4
   • These abnormalities often correlate with COVID-19 severity and inflammatory markers 3, 4

2. Reproductive hormone considerations:

   • Perimenopausal fluctuations may exacerbate long COVID symptoms 1
   • Menstrual cycle changes are reported in 10-30% of women post-COVID 1
   • Pre-menstrual period has been identified as a trigger for long COVID symptom flares 1

3. Fatigue assessment algorithm:

   • If thyroid function is abnormal → treat thyroid dysfunction
   • If thyroid function is normal → evaluate for:
     • Dysautonomia/POTS (postural orthostatic tachycardia syndrome) - present in up to 67% of long COVID patients 1
     • Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patterns 1
     • Deconditioning (common post-COVID even after mild infection) 1

Clinical Pearls and Pitfalls

• Important: Normal laboratory values do not rule out long COVID. Long COVID is a clinical diagnosis that doesn't require positive inflammatory markers 2
• Caution: Thyroid abnormalities may resolve spontaneously after acute COVID-19, but incident thyroid autoimmunity may develop 6, 7
• Key consideration: Fatigue in long COVID is multifactorial and may persist despite normal hormone levels 7
• Timing matters: Evaluate hormone levels in relation to menstrual cycle phase in perimenopausal women, as fluctuations may influence symptom severity 1
• Follow-up: Schedule regular reassessment of thyroid function, as patterns may evolve over time 2

Remember that fatigue is one of the most common long COVID symptoms (31-58% of patients) 2, and while hormone testing is important, a comprehensive approach addressing multiple potential mechanisms is essential for effective management.