Secondary amenorrhea

• Etiology
  • Pregnancy: most common cause of secondary amenorrhea
  • Ovarian disorders (e.g., premature ovarian failure, polycystic ovary syndrome)
  • Hypothyroidism (↓ T3/T4 → ↑ TRH → ↑ prolactin → ↓ GnRH → ↓ estrogens)
  • Hyperthyroidism
  • Hyperprolactinemia
  • Cushing syndrome
  • Hypergonadotropic hypogonadism
  • Hypogonadotropic hypogonadism
  • Functional hypothalamic amenorrhea: a dysfunction in the pulsatile secretion of GnRH
    • Etiology
      • Excessive exercise: e.g., in competitive athletes (also called exercise-induced amenorrhea)
      • Reduced calorie intake (e.g., in eating disorders like anorexia nervosa)
      • Stress
      • Female athlete triad syndrome: menstrual dysfunction, calorie deficit, and decreased bone density in athletic female young adults or adolescents
    • Pathophysiology: decreased leptin (low body fat) and/or increased cortisol (exercise/stress) → decreased pulsatile release of GnRH from the hypothalamus → decreased secretion of FSH and LH → decreased estrogen levels → anovulation and secondary amenorrhea → infertility