When should an endometrial biopsy be performed?

When to Perform Endometrial Biopsy

Endometrial biopsy should be performed in postmenopausal women with abnormal uterine bleeding, women with endometrial thickness ≥4mm on ultrasound (postmenopausal) or ≥10mm (premenopausal), and in women with Lynch syndrome for cancer surveillance. The procedure is essential for early detection of endometrial cancer, which significantly impacts mortality and quality of life outcomes.

Primary Indications for Endometrial Biopsy

Postmenopausal Bleeding

• Mandatory investigation for all women with postmenopausal bleeding 1
• Diagnostic pathway:
  1. Transvaginal ultrasound to measure endometrial thickness
  2. Endometrial biopsy for endometrial thickness ≥3-4mm 1
  3. If initial biopsy is negative but bleeding persists, proceed to fractional D&C under anesthesia 1

Abnormal Premenopausal Bleeding

• Indicated for:
  • Women over age 45 with abnormal uterine bleeding
  • Women with persistent intermenstrual bleeding (higher risk than heavy menstrual bleeding) 2
  • Endometrial thickness ≥10mm on ultrasound 3
  • Failed medical management of abnormal uterine bleeding
  • Risk factors for endometrial cancer (obesity, diabetes, hypertension, PCOS)

Genetic Risk Factors

• Annual endometrial biopsy recommended for women with Lynch syndrome 1
• Women with Lynch syndrome have up to 60% lifetime risk of endometrial cancer 1
• Allows for cancer surveillance while preserving fertility until childbearing is complete

Thickened Endometrium on Imaging

• Postmenopausal women: Biopsy if endometrial thickness ≥3-4mm 1, 4
• Postmenopausal women with endometrial volume ≥3mL 4
• Premenopausal women: Biopsy if endometrial thickness ≥10mm 3

Procedural Considerations

• Office-based procedure with high sensitivity (97-99%) for detecting endometrial cancer 1
• False-negative rate of approximately 10% 1
• If initial biopsy is negative but symptoms persist, proceed to fractional D&C under anesthesia 1
• Consider hysteroscopy for persistent/recurrent undiagnosed bleeding or to evaluate focal lesions 1

Special Considerations

• Pregnancy is the only absolute contraindication 5
• For postmenopausal women with fibroids and abnormal bleeding, endometrial biopsy must be performed to rule out malignancy before any minimally invasive treatments 1
• Risk of endometrial cancer increases with age, particularly in women >60 years 4
• Common adverse effect is cramping; serious complications are rare 5

When to Refer for Additional Evaluation

• Failed procedure or insufficient sample 5
• Persistent or recurrent symptoms despite normal biopsy results 5
• Initial biopsy showing limited benign surface endometrium (may indicate insufficient sampling) 6
• Women with increased BMI and limited initial sampling have higher risk of subsequent atypia or malignancy 6

Endometrial biopsy is a cornerstone diagnostic procedure for evaluating the endometrium, with its primary value being the early detection of endometrial hyperplasia and cancer, which directly impacts patient survival and quality of life.