Endometrial Thickening

Introduction

• There is no defined “normal” endometrial thickness post-menopause-in postmenopausal women without bleeding. 
   
• For women not on HRT, if the endometrial thickness is found to be 10mm or more - fast track suspected gynaecological referral is required due to the risk of malignancy. 
   
• For women on HRT, if the endometrial thickness is found to be 10mm or more- refer to the Menstrual Disorders Clinic. 
   
• Postmenopausal endometrial thickening is often caused by: benign endometrial polyp(s), tamoxifen, sub-mucus fibroids, uterine malformations, synechiae, adenomyosis and artefact owing to uterine lie/axial uterus.
   
• Women should be advised to report any incidence of PMB or unscheduled bleeding if on HRT. 

 

In scope   

• Incidental finding of endometrial thickening in women with no postmenopausal bleeding (PMB) or abnormal discharge

 

Not in scope    

• Post Menopausal Bleeding (PMB) For Women Not On HRT
  
  
• Unscheduled Bleeding (USB) on Hormone Replacement Therapy (HRT)                                                  

 

Red Flag Features

 Consider risk factors for endometrial cancer:

• Family history
   
• Obesity
   
• Insulin Resistance (eg PCOS, T2DM)
   
• Nulliparity
   
• Tamoxifen use
   
• Late menopause (>55 years)

 

Investigations required prior to referral

This is an incidental diagnosis made on ultrasound.

• The endometrial thickness measured is the total thickness – i.e. polyp plus endometrium (not length of polyp).

 

 

Management Optimisation

• If the patient has PMB (and is not on HRT) please see Post Menopausal Bleeding (PMB) For Women Not On HRT
  
  
• If the patient is on HRT AND has had unscheduled bleeding please see Unscheduled Bleeding (USB) on Hormone Replacement Therapy (HRT)
   

Note the criteria of endometrial thickness (>4mm for Continuous combined HRT (CCT) and 7mm for sequential combined HRT (SCT) are only for unscheduled bleeding on HRT rather than an incidental finding of endometrial thickening whilst on HRT in a women with no PV bleeding.

 

Advice and Guidance

Request advice and guidance by emailing Gynaecology via eRS. 

 

Referral for asymptomatic endometrial thickening

Fast track suspected gynaecological referral is required if:

• NOT on HRT AND asymptomatic and endometrial thickness + polyp (if present) ≥ 10mm OR suspicious endometrium on TV USS
   
• Symptomatic of PMB.

 

Urgent Referral to Menstrual Disorders Clinic

• On HRT AND asymptomatic and endometrial thickness + polyp (if present) ≥ 10mm.

 

Supporting Information

For patients     

• RCHT 1797 Post menopausal bleeding

 

References        

• RCHT Post Menopausal Bleeding Service Guideline
• Journal of Obstetrics and Gynaecology Canada
• Guideline No. 451: Asymptomatic Endometrial Thickening in Postmenopausal Women
• July 2024

 

Page Review Information

Review date	11 March 2026
Next review date	11 March 2028
Clinical editor	Dr Melanie Schick
Contributors	Miss Sophia Julian, Consultant Gynaecologist, RCHT