What is the initial workup for postmenopausal bleeding (PMB)?

Initial Workup for Postmenopausal Bleeding (PMB)

All women with postmenopausal bleeding should be referred urgently for evaluation, with transvaginal ultrasound (TVUS) as the first-line screening test, followed by endometrial sampling if endometrial thickness is ≥5mm. 1, 2

Definition and Significance

Postmenopausal bleeding is defined as any vaginal bleeding occurring 12 months or more after the last menstrual period. It affects up to 10% of women over age 55 and requires thorough evaluation due to the risk of malignancy 2.

Initial Assessment

History

• Duration and pattern of bleeding
• Risk factors for endometrial cancer:
  • Obesity (BMI >30)
  • Diabetes mellitus
  • Hypertension
  • Lynch syndrome (30-60% lifetime risk)
  • Unopposed estrogen exposure
• Medication history (HRT, tamoxifen, anticoagulants)

Physical Examination

• Abdominal examination for masses
• Pelvic examination including:
  • Speculum examination to identify source of bleeding
  • Assessment for vaginal atrophy
  • Evaluation for cervical abnormalities or polyps
  • Bimanual examination to assess uterine size and adnexal masses

Diagnostic Algorithm

1. Transvaginal Ultrasound (TVUS)

   • First-line imaging modality for all women with PMB 1
   • Measures endometrial thickness and evaluates for structural abnormalities
   • Endometrial thickness ≤4mm has nearly 100% negative predictive value for endometrial cancer 1

2. Endometrial Sampling

   • Indicated when:
     • Endometrial thickness ≥5mm on TVUS
     • Abnormal endometrial echogenicity or texture regardless of thickness
     • Persistent bleeding despite normal TVUS
   • Options include:
     • Office endometrial biopsy (Pipelle has 99.6% sensitivity for endometrial carcinoma) 1
     • Hysteroscopy with directed biopsy (superior for focal lesions)
     • Dilation and curettage (D&C) under anesthesia

3. Additional Imaging

   • Saline infusion sonohysterography
     • Helpful when TVUS suggests focal pathology 1
   • MRI, CT, or PET
     • Reserved for evaluating suspected extrauterine disease 1

Management of Inadequate Samples

• Office endometrial biopsies have approximately 10% false-negative rate 1
• If initial sampling is inadequate or negative with persistent symptoms:
  • Proceed to fractional D&C under anesthesia 1
  • Consider hysteroscopy for direct visualization and targeted biopsy

Common Causes of PMB

• Atrophic endometritis/vaginitis (58.8%) 3
• Endometrial polyps (9.4%) 3
• Endometrial carcinoma (9.4-10%) 2, 3
• Cervical carcinoma (6%) 3
• Submucous fibroids
• Endometrial hyperplasia
• Non-gynecological causes (e.g., urethral caruncle, rectal bleeding)

Important Considerations

• The overall incidence of genital tract malignancies in patients with PMB is approximately 16% 4
• Hysteroscopy with D&C provides higher diagnostic accuracy than blind sampling techniques for detecting focal lesions 1
• If endometrial thickness is <5mm, examination is normal, and bleeding has stopped, no further action may be needed 2
• Serum CA-125 may be helpful for monitoring clinical response in patients with extrauterine disease 1

Referral Guidelines

• Immediate referral to gynecologic oncologist if malignancy is detected
• Urgent referral for all women with PMB, even if symptoms resolve spontaneously 2

Remember that while most causes of PMB are benign, prompt and thorough evaluation is essential to exclude malignancy, which occurs in approximately 10% of cases.