Amenorrhea

Amenorrhea

 

Amenorrhea is defined as the absence of menstrual flow.

Epidemiology

  • Prevalence – 3-4% when not due to pregnancy, lactation or menopause
    • Secondary amenorrhea more common than primary amenorrhea

Classifications

  • Primary – lack of menstrual flow by age 14 in the absence of secondary sexual characteristics or age 16 if secondary sexual characteristics are present
    • Etiology (most common)
      • Androgen insensitivity
      • Congenital adrenal hyperplasia
      • Congenital anomalies
      • Constitutional delayed puberty
      • Eating disorder
      • Excessive exercise
      • Gonadal dysgenesis
        • Turner syndrome (diagnose by chromosome analysis)
      • Hyperprolactinemia
      • Primary ovarian failure
  • Secondary – have secondary sexual characteristics and previous menstrual flow but no menstrual flow for 3 months in women with previously normal menstruation or for 9 months in women with previous oligomenorrhea
    • Etiology (most common)
      • Polycystic ovarian syndrome (PCOS)
      • Hypothyroidism
      • Hyperprolactinemia
      • Eating disorder, excessive exercise
      • Pituitary disease
      • Depression
      • Ovarian failure
      • Medication-induced
        • Antidepressants
        • Antipsychotics
        • Chemotherapy
      • Tumor
      • Pituitary
      • Craniopharyngioma
      • Fragile X syndrome

Pathophysiology

  • Normal menses require developed endometrium, normal outflow tract and functioning hypothalamic-pituitary-ovarian axis
  • Hypothalamus secretes gonadotropin releasing hormone (GnRH) causing anterior pituitary release of follicle stimulating hormone (FSH) and luteinizing hormone (LH)
  • LH and FSH surge stimulates the ovary to secrete estrogen, progestin and androgen
  • FSH causes a follicle to be dominant and release an ovum (thought to be from LH spike)
  • Progestin from corpus luteum suppresses FSH and LH
  • Without fertilization, the corpus luteum involutes, estrogen and progestin levels fall and menses occur
  • Interruption in pathway can result in amenorrhea

Clinical Presentation

  • Primary – may have absence of secondary sexual characteristics or congenital anomalies of the urogenital system
  • Secondary – body habitus consistent with PCOS, anorexic body habitus, galactorrhea, excessive facial hair

Diagnosis

  • Indications for testing – presence of amenorrhea without identifiable cause
  • Laboratory testing
    • Exclude pregnancy – urinary or serum BHCG
    • Initial evaluation of secondary amenorrhea – FSH, LH, prolactin, estrogen, thyroid stimulating hormone
    • Initial evaluation of primary amenorrhea – TSH, prolactin, LH, FSH
    • Secondary evaluation – may include testosterone, dehydroepiandrosterone, sulfate (DHEAS) and estradiol
    • Chromosome analysis for X chromosome abnormalities
  • Imaging studies
    • Pelvic ultrasound (US), transvaginal US
    • Head MRI

Differential Diagnosis

  • Most common diseases to rule out are in the prior section titled "Classifications"
  • Thyroid disease
  • Pregnancy

See Also