Menses

Primary Dysmenorrhea

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Primary Dysmenorrhea, Essential Dysmenorrhea

  • See Also
  1. Dysmenorrhea
  2. Secondary Dysmenorrhea
  3. Acute Pelvic Pain
  4. Chronic Pelvic Pain
  • Epidemiology
  1. Onset occurs within 6 to 12 months of Menarche (may occur as long as 2 years from Menarche in some women)
  2. Prevalence peaks around age 20 years
  3. Lifetime Prevalence of severe Dysmenorrhea: 50-60%
  4. Women incapacitated for 1-3 days of each cycle: 10%
  • Pathophysiology
  1. No clear pelvic pathology
    1. Contrast with Secondary Dysmenorrhea in which an underlying organic etiology is identified
  2. Hormonal and inflammatory level increases with no clear pelvic pathology
    1. Increased Leukotriene levels
    2. Uterine hyperactivity with increased uterine contractility and cramping
      1. Increased myometrial resting tone >10 mmHg
      2. Increased contractile myometrial pressure >120 mmHg
      3. Increased frequency of uterine contractions
      4. Dysrhythmia of uterine contractions
    3. Increased Prostaglandin levels
      1. Increase in enzyme Prostaglandin Synthetase
      2. Increased Prostaglandins result in Vasoconstriction
      3. Prostaglandin mediated nerve terminal Hypersensitivity with high intensity contractions
    4. Vasopressin-mediated contractions
      1. Reduces uterine Blood Flow via Vasoconstriction
      2. May result in ischemic pain from uterine Hypoxia (uterine Angina)
  • Symptoms
  1. See Dysmenorrhea
  2. Onset occurs within 6 to 12 months of Menarche and recurrs with each Menstrual Cycle
  • Examination
  1. See Dysmenorrhea
  2. Normal pelvic examination
  • Differential Diagnosis
  1. See Secondary Dysmenorrhea
  • Labs
  1. See Dysmenorrhea
  2. Urine Pregnancy Test
  3. Urinalysis
  4. Chlamydia PCR
  5. Gonorrhea PCR
  • Precautions
  1. Primary Dysmenorrhea is a diagnosis of exclusion
  2. Exclude Secondary Dysmenorrhea causes (at minimum: pregnancy, Urinary Tract Infection and Sexually Transmitted Infection
    1. Older women without prior history of Dysmenorrhea should be assumed to have Secondary Dysmenorrhea until thorough evaluation is completed
    2. In young women, Secondary Dysmenorrhea still accounts for 10% of cases (especially due to Endometriosis)
  • Management
  1. See Dysmenorrhea
  • References
  1. Dawood (2006) Obstet Gynecol 108(2): 428-41 [PubMed]
  2. McKenna (2021) Am Fam Physician 104(2): 164-70 [PubMed]
  3. Osayande (2014) Am Fam Physician 89(5): 341-6 [PubMed]