What is the treatment for primary amenorrhea (absence of menstruation) in a 19-year-old girl?

Treatment for Primary Amenorrhea in a 19-Year-Old Girl

The treatment for primary amenorrhea in a 19-year-old girl should be based on the underlying cause, with hormone replacement therapy recommended for those diagnosed with premature ovarian insufficiency, while addressing energy deficiency, excessive exercise, or stress for those with functional hypothalamic amenorrhea. 1, 2

Diagnostic Evaluation

Before initiating treatment, a thorough diagnostic evaluation is essential:

1. Initial Laboratory Tests:

   • Pregnancy test
   • FSH, LH, estradiol
   • Prolactin
   • TSH
   • Consider karyotype analysis if hypergonadotropic hypogonadism is suspected 2, 3

2. Categorization of Amenorrhea Based on Hormone Levels:

   • Elevated FSH/LH: Suggests primary ovarian insufficiency
   • Normal/Low FSH/LH with normal prolactin and TSH: Suggests functional hypothalamic amenorrhea
   • Normal/Elevated LH with normal/low FSH: Consider polycystic ovary syndrome 2

3. Additional Evaluation:

   • Pelvic ultrasound to assess endometrial thickness, ovarian morphology, and rule out anatomical abnormalities
   • DXA scan if amenorrhea ≥6 months, history of stress fractures, or BMI <17.5 kg/m² 2

Treatment Based on Etiology

1. Primary Ovarian Insufficiency (POI)

If FSH is elevated (>35 IU/L) and LH is elevated (>11 IU/L):

• Hormone Replacement Therapy (HRT) is the mainstay of treatment 1, 2

  • Transdermal estradiol (100 μg patch twice weekly) with cyclic oral progesterone (200 mg for 12 days each month)
  • This regimen supports bone health and development of secondary sexual characteristics
  • Continue until the typical age of menopause (around 50 years)

• Bone Health Protection:

  • Ensure calcium intake of 1000-1300 mg/day
  • Vitamin D supplementation to maintain levels between 32-50 ng/mL
  • Weight-bearing exercise 2

2. Functional Hypothalamic Amenorrhea (FHA)

If FSH/LH are normal or low:

• Address Energy Deficiency:

  • Increase caloric intake by 20-30% over baseline energy needs
  • Target energy availability ≥45 kcal/kg fat-free mass/day
  • Aim for weight gain of approximately 0.5 kg every 7-10 days 2

• Modify Exercise Patterns:

  • Reduce training volume if excessive
  • Focus on weight-bearing activities that support bone health 2

• Address Psychological Stressors:

  • Cognitive behavioral therapy (CBT) is effective, particularly for patients with disordered eating behaviors
  • Address body image concerns 2

• Consider Hormonal Support:

  • If amenorrhea persists despite lifestyle modifications, consider hormonal therapy similar to POI treatment
  • This is particularly important for bone health protection 2

3. Anatomical Abnormalities

If Müllerian agenesis or other anatomical abnormalities are identified:

• Surgical Intervention:

  • Vaginoplasty may be considered for vaginal agenesis
  • Correction of outflow tract obstructions if present 4, 5

• Hormonal Support:

  • If functional ovaries are present but anatomical abnormalities prevent menstruation, hormonal therapy may not be needed for physiological purposes
  • However, cyclic hormonal therapy may provide psychological benefit 6

Monitoring and Follow-up

• Regular assessment of menstrual function
• Weekly weight monitoring when initiating treatment for FHA
• Repeat hormone testing based on clinical response
• Bone density monitoring with DXA scan every 1-2 years 2

Special Considerations

• Fertility Concerns:

  • Patients with POI should not be presumed infertile as they can maintain unpredictable ovarian function 3
  • For women desiring pregnancy with FHA, pulsatile GnRH therapy is preferred over gonadotropins for ovulation induction
  • BMI should be ≥18.5 kg/m² before ovulation induction 2

• Long-term Health:

  • Untreated amenorrhea increases risk for cardiovascular disease and irreversible bone loss
  • Early intervention is crucial, especially during this critical period for bone mass accrual 2

When to Refer

Referral to endocrinology/gynecology specialist is indicated for:

• Complex cases
• Müllerian anomalies
• Hypergonadotropic hypogonadism
• Persistent amenorrhea despite initial management 2

Common Pitfalls to Avoid

• Delayed Diagnosis: Amenorrhea lasting >3 months should not be accepted as normal
• Incomplete Evaluation: Always perform a genital examination, even if "normal" sexual activity is reported 5
• Missing Associated Conditions: Screen for eating disorders in patients with FHA
• Inadequate Bone Health Monitoring: Delaying treatment can result in irreversible bone loss 2