Endometrial Thickness Threshold for Endometrial Evaluation in Postmenopausal Women

Thresholds for Intervention

In postmenopausal women, an endometrial thickness ≥ 5 mm on transvaginal ultrasound should trigger endometrial tissue sampling (biopsy, D&C, or hysteroscopy) to assess for malignancy or hyperplasia. This recommendation is strongly supported by the American College of Radiology (ACR) Appropriateness Criteria (2020). 1

An endometrial thickness ≤ 4 mm provides a negative predictive value > 99 % for endometrial cancer, allowing clinicians to safely forgo invasive evaluation in this range. Evidence is derived from ACR data (2020) and reflects a high‑strength recommendation. 1

Transvaginal ultrasound cannot determine the underlying cause of a thickened endometrium; it only quantifies thickness. This limitation is highlighted by the ACR (2020). 1
Abnormal echogenicity or heterogeneous texture of the endometrium on ultrasound is associated with significant pathology independent of measured thickness, indicating that visual characteristics must also guide decision‑making (ACR, 2020). 1

Step 1 – First‑line test: Perform transvaginal ultrasound in any postmenopausal woman presenting with bleeding (ACR, 2020). 1
Step 2 – Thickness ≤ 4 mm: Opt for observation without immediate biopsy, given the > 99 % NPV for cancer (high‑strength evidence). 1
Step 3 – Thickness ≥ 5 mm: Proceed to endometrial tissue sampling (biopsy, D&C, or hysteroscopy) to rule out malignancy (strong recommendation). 1
Step 4 – Inadequate visualization or abnormal sonographic appearance: Conduct tissue sampling regardless of measured thickness, because abnormal echogenicity/texture signals possible pathology (high‑strength evidence). 1