Endo Fha Correct Energy Imbalance

Correct energy imbalance to improve HPO axis function

STEP 1 — Gather Information

Collect detailed dietary recall (caloric intake, macronutrients), exercise log (type, frequency, duration), weight and height (BMI), menstrual history (duration of amenorrhea), and signs of energy deficit (low leptin, amenorrhea, weight loss, excessive exercise); then proceed to assess whether an energy deficit is present.

STEP 2 — Rule In / Rule Out

If the patient demonstrates low energy availability (e.g., BMI <18.5 kg/m2, recent weight loss, caloric intake <30 kcal/kg fat-free mass/day, or exercise expenditure exceeding intake), rule in energy deficit–related FHA and go to Step 3; otherwise, rule out energy deficit as primary cause and evaluate for other etiologies (e.g., PCOS, thyroid dysfunction, hyperprolactinemia).

STEP 3 — Classify or Stratify

Stratify the energy deficit as mild (BMI 18.5–20, modest caloric deficit), moderate (BMI 17.5–18.5, clear deficit), or severe (BMI <17.5, marked weight loss or excessive exercise); this classification determines the intensity of intervention needed.

STEP 4 — Decide

For mild deficit: increase caloric intake by 250–500 kcal/day and maintain current exercise; for moderate deficit: increase intake by 500–750 kcal/day and reduce exercise by 30%; for severe deficit: increase intake by 750–1000 kcal/day, reduce exercise by 50%, and consider supervised nutritional rehabilitation; in all cases, aim for gradual weight gain of 0.5–1 kg/month until BMI ≥18.5 kg/m2 and monitor for return of menses.

Clinical Guardrails / Mimics / Pitfalls

Do not prescribe oral contraceptives solely to induce menses without addressing energy imbalance; avoid recommending weight gain in patients with normal or high BMI without documented energy deficit; do not overlook comorbid eating disorders or psychological stressors that require concurrent therapy; avoid excessive exercise restriction that could impair bone health; ensure calcium and vitamin D adequacy during refeeding.

Concrete Clinical Example

A 19‑year‑long‑distance runner presents with 8 months of amenorrhea, BMI 17.2 kg/m2, runs 50 miles/week, and reports intake of 1600 kcal/day. She is classified as moderate energy deficit. Intervention: increase intake to 2300 kcal/day (≈+700 kcal), reduce running to 20 miles/week, ensure 1500 mg calcium and 800 IU vitamin D daily. After 4 months she gains weight to BMI 18.8 kg/m2 and reports resumption of menses.

Source: Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2017, DOI:10.1210/jc.2017-00131