Updated: 5/8/2019

Primary Dysmenorrhea

Review Topic
  • An 18-year-old nulligravid college woman complains of cramping lower  abdominal painduring menses for the past three years. She has nausea and vomiting during menses, but denies irregular or heavy periods, pain with intercourse, or abdominal pain outside of menses. Pelvic exam is normal.
  • Definition
    • dysmenorrhea is painful menses
    • primary dysmenorrhea
      • crampy, lower abdominal pain occurring during menses without any clear disease that can explain the symptoms
    • secondary dysmenorrhea 
      • pain can be explained by other conditions (e.g., uterine fibroids, endometriosis, adenomyosis, PID)
  • Epidemiology
    • prevalence
      • 50-90% of reproductive-age women worldwide experience painful menses, with risk decreasing with increased age.
    • risk factors
      • smoking
      • long, heavy or irregular periods
      • decreased age at menarche
      • age < 30
  • Pathogenesis
    • prostaglandins are released at the beginning of menses, causing high frequency uterine contractions and increased intrauterine pressures
    • when uterine pressure is greater than arterial pressure, there is uterine ischemia, and the accumulated metabolites stimulate type C neural pain fibers resulting in dysmenorrhea
  • History
    • typically begins in adolescence, a few years after menarche
    • crampy, intermittent midline lower abdominal pain, which may radiate to lower back or thighs
    • begins 1-2 days before menses and lasts up to 72 hours
  • Associated symptoms
    • nausea 
    • vomiting
    • headache
    • fatigue
    • malaise
  • Modifying factors
    • improves with age, after childbirth, with NSAIDs
  • Physical exam
    • normal
  • No labs or physical findings that are suggestive of primary dysmenorrhea
  • Need to rule out secondary dysmenorrhea
  • History and physical suggestive of secondary dysmenorrhea
    • age of onset > 25 yrs
    • nonmidline pelvic pain
    • abnormal uterine bleeding
    • absence of nausea, vomiting, or other associated symptoms
    • abnormal pelvic exam
    • dyspareunia or dyschezia
Differential Diagnosis
  • Primary dysmenorrhea
  • Secondary dysmenorrhea
    • adenomyosis
    • endometriosis
    • uterine fibroids
    • pelvic inflammatory disease
  • Miscarriage and ectopic pregnancy
  • Midcycle pain (mittelschmerz)
    • recurrent lower abdominal/pelvic pain that occurs mid-menstrual cycle
      • ~2 weeks after last menses
    • associated with ovulation
      • enlargement and rupture of follicular cyst
  • Supportive treatment
    • heat packs
    • exercise
  • NSAIDS (prostaglandin inhibitors)  
    • ibuprofen
    • naproxen
  • Hormonal therapy
    • estrogen-progestin contraceptives are first-line (e.g., OCP, transdermal patch, vaginal ring)
    • progestin-only contraceptives may also be used
Prognosis, Prevention, and Complications
  • For women who complete 3 months of NSAIDs and/or hormonal therapy with no improvement, diagnostic laparoscopy is an option to look for hidden endometriosis or other pelvic pathology 

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Questions (3)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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(M2.GN.4740) A 15-year-old female presents to her pediatrician’s office for severe menstrual cramping. The patient underwent menarche at age 11, and her periods were irregular every 2-3 months for two years. After that, her cycles became roughly regular every 28-35 days, but she has had extremely painful cramps and often has to miss school. The cramps are intermittent and feel like a dull ache in the center of her abdomen, and there is usually accompanying back pain. The patient has been using heating pads with limited relief. She reports some periods being “really heavy” and requires a superabsorbent pad every 6 hours for 2 days each cycle, but this does not limit her activities. She denies any bowel or bladder changes. The patient had normal development throughout childhood, is on the soccer team at school, and is not sexually active. Her father has hypertension and her mother has endometriosis and heavy periods. On exam, the patient is 5 feet 5 inches and weighs 158 pounds (BMI 26.3 kg/m^2). She is well appearing and has no abdominal tenderness. She has Tanner IV breasts and Tanner IV pubic hair, and external genitalia are normal. Which of the following is the best next step for this patient’s menstrual cramps? Review Topic

QID: 108647

Von Willebrand factor antigen assay




Pelvic ultrasound




MRI of the pelvis








Increased exercise




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