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Unscheduled Bleeding (USB) on Hormone Replacement Therapy (HRT)


Please note that:

  • this guidance differs from the BMS Management of unscheduled bleeding on hormone replacement therapy (HRT), April 2024
  • currently there are no plans on changing the Post Menopausal Bleeding (PMB)/USB pathway in CIOS.  

 

Introduction

  • Up to 80% of women will experience unscheduled bleeding or spotting in the first 6 months of combined HRT treatment
  • The incidence of cancer in women who experience unscheduled bleeding on HRT is <1:200.  USB whilst on HRT is unlikely to indicate endometrial pathology.

 

Normal bleeding on HRT

  • Continuous HRT (CCT)- no bleeding is expected once the patient is stable on this regime which usually takes 6 months
  • Sequential HRT (SCT)- cyclical bleeding usually at the end of the progesterone phase.


In scope       

  • USB on HRT

 

Not in scope 


  

Red Flag Features

  • Examination findings suggestive of gynaecological cancer
     
  • Family history of endometrial cancer or Lynch Syndrome
     
  • Unscheduled bleeding on HRT AND ≥ 65 years
     
  • Unscheduled bleeding on HRT AND BMI ≥ 40
     
  • Bleeding that continues for ≥6 weeks after stopping HRT.

Investigations required prior to referral

No investigations are required prior to Fast Track Suspected Cancer referral.  The PMB clinic will arrange a transvaginal (TV) ultrasound.


 

Management optimisation

  • Offer examination to rule out other causes of vaginal bleeding eg. Vulvovaginal atrophy or any vaginal/vulval/cervical pathology
     
  • If any vaginal/vulval/cervical pathology is suspected then refer if appropriate using fast track suspected gynaecological cancer form or manage vulvo/vaginal atrophy once malignancy is excluded.

 

 

Overview of Fast Track Referral Process for USB on HRT

 

If the patient is under 65 years and BMI < 40 with USB and does not wish to stop HRT

Consider requesting an urgent TV ultrasound scan to calculate the endometrial thickness. 


If the endometrium is fully visualised and measures:

  • ≤ 4 mm with CCT

or

  • ≤7 mm with SCT

 

Then reassure and consider adjusting HRT regime.

  • If the endometrium is not fully visualised

or

  • >4 mm for CCT

or

  • > 7mm for SCT

 

Then make an urgent referral to the Menstrual Disorders Clinic. The patient will booked for an outpatient hysteroscopyat their first visit.


 

When can bleeding on HRT be expected?

  • Bleeding which clearly follows one or two missed progesterone doses can usually be ignored, but unopposed oestrogen for long periods is a risk for endometrial cancer
     
  • Bleeding within 6 months of starting continuous combined HRT is common (80% women) and does not usually require action
     
  • Bleeding within 3 months of a change in sequential HRT is common and does not usually require action.

 

How to change Progesterone to manage unscheduled bleeding

If: BMI < 40 and age < 65 years and bleeding settles within 6 weeks of stopping HRT (and endometrium is fully visualised with normal thickness on USS if done) ie does not meet fast track criteria:

 

Unscheduled bleeding on HRT with Mirena IUS

  • Those with an “in date” Mirena IUS, i.e. within 5 years of insertion are very unlikely to develop endometrial cancer (note licenced for 4 years but safely used for 5 years as per FSRH advice for endometrial protection with HRT).
     

Consider adding in addition to Mirena:

  •  Provera 5-10mg at night

or

  •  Utrogestan 100-200mg at night 

 

Unscheduled bleeding on SCT

Consider poor compliance, drug interactions and malabsorption problems.

  • If the withdrawal bleeding is heavy or prolonged, increasing the dose or changing the type of progestogen, or reducing the dose of oestrogen may help
     
  • If bleeding occurs early in the progestogen phase, increase the dose, or change the type of progestogen

  • If spotting occurs before the withdrawal bleed, a higher oestrogen dose could be tried
     
  • If there is irregular bleeding, change the regime or increase the progestogen dose
     
  • In the case of painful bleeding, change the type of progestogen.

 

Options to increase the dose or change type of progesterone on SCT:

  • 200mg Utrogestan for 3 weeks on 1 week off  OR 300mg 2 weeks on and 2 weeks off.  Taken at night
     
  • Increase Provera to 20mg  2 weeks on, 2 weeks off at night

 

Unscheduled bleeding on CCT

Options to increase the dose or change the type of progestogen on CCT:

  • Increase Utrogestan to 200mg at night OR Provera up to 30mg (lowest effective dose) at night
     
  • Fit a 52 mg levonorgestrel-releasing intrauterine system (e.g. Mirena)
     
  • If all other options do not work, then consider changing to sequential HRT (SCT).


 

Patients with ongoing PMB that has been previously investigated

If the patient experiences persistent PMB within 6 months of previous investigation for PMB, and has undergone hysteroscopy and biopsy, consider other causes:

  • HRT problems – a small amount of bleeding after inserting vaginal oestrogen HRT is normal.
     
  • Vulvovaginal or endometrial atrophy (vaginal oestrogen HRT can take up to 6 months to be effective).
     
  • Submucous fibroids on ultrasound.


 

Advice and Guidance 

Contact the Menopause Advice & Guidance service by email for queries about changing HRT. 


 

Information required for Referral

  • Abdominal and pelvic examination are required to identify any pelvic mass or vaginal/vulval/cervical pathology.  If a suspected malignancy is identified, refer appropriately on the fast track suspected gynaecological cancer form

  • BMI
     
  • HRT regime

 

Referral Criteria

Suspected Endometrial Cancer

Refer women on the Fast track suspected gynaecological cancer form for suspected endometrial cancer with either:

  • Unscheduled Bleeding on HRT AND ≥ 65 years
     
  • Unscheduled Bleeding on HRT AND BMI ≥ 40
     
  • Bleeding that continues for ≥ 6 weeks after stopping HRT

 

Benign gynaecology clinic

Refer to benign gynaecology clinic for consideration of direct access hysteroscopy if patients fall outside of the fast track criteria and the results of TV USS are available, showing:

  • the endometrium is not fully visualised

or

  • >4 mm for CCT

or

  • > 7mm for SCT


Then make an urgent referral to the Menstrual Disorders Clinic. The patient will booked for an outpatient hysteroscopyat their first visit.



 

Supporting Information

For professionals

 

For patients 

 

References

 

Page Review Information

 

Review date

27 June 2025

Next review date

27 June 2027

Clinical editor

Dr Melanie Schick

Contributors

Miss Sophia Julian, Consultant Gynaecologist, RCHT

Dr Jo Parry, GP