Unscheduled or Unexpected Bleeding while taking Hormone Replacement Therapy

Unscheduled bleeding (bleeding that is not expected) while taking Hormone Replacement Therapy (HRT) is a common problem. Bleeding within the first six months of starting HRT, or within three months of changing the dose of HRT, is common. If bleeding happens after this time, a transvaginal ultrasound scan is recommended. This is where a small probe with a rounded end is inserted into the vagina. This scan is done to help assess the risk of endometrial cancer (cancer of the lining of the womb).

The risk of endometrial cancer when experiencing bleeding while taking HRT is low (one in 100). The transvaginal ultrasound scan measures the thickness of the lining of the womb. It also looks for any ovarian cysts. If the lining of the womb is thickened, or an ovarian cyst is found, you will be referred to a Gynaecology Cancer Clinic for more tests. This will be within two weeks of your ultrasound.

If the lining of my womb is thickened, does it mean I have cancer?

If you have a thickened womb lining, the risk of cancer is still low. When you attend the clinic, you will be seen by a gynaecologist. They will ask questions about your symptoms, general health, previous medical conditions, and what HRT you are taking – it would be useful to bring a copy of your HRT prescription with you. Once they have done this, you may be offered an examination and a hysteroscopy.

During a hysteroscopy, a thin tube with a camera inside is inserted into your womb via your cervix to look at the lining of your womb. Sterile (purified) water is injected through the tube, to make it easier to see inside your womb. Most people cope well with the hysteroscopy without anaesthetic. For those who find it painful, it can be done under general anaesthetic at a later date. A hysteroscopy looks for the presence of cancer in the lining of the womb. It can also diagnose polyps (a non-cancerous growth of the womb). In some clinics, they may offer to remove any polyps at the same time. They may also take a biopsy (a sample for further testing) of the womb lining. This is to be certain that there is no evidence of cancer. The result of a biopsy may take a few weeks to come back. Results are often sent to you by letter. You can telephone the gynaecology service using the contact details at the end of this leaflet if you have not received your results after six weeks.

What happens if I have a normal lining of the womb, but I am still bleeding?

Before referring you for a transvaginal ultrasound, your GP will have checked for other causes of bleeding, such as an infection.

Bleeding while taking HRT is often caused by an imbalance in the hormones oestrogen and progesterone. Oestrogen helps improve menopausal symptoms. Progesterone helps protect the womb from bleeding and from cancer. Increasing the dose of progesterone or changing to a different type of progesterone may reduce the chances of bleeding. If menopausal symptoms can be managed with a lower dose of oestrogen, this can also reduce the risk of bleeding. Your GP will be able to help with this.

It is important that you take your HRT medication as advised by your GP. If you miss any doses, this can also trigger bleeding.

If the bleeding carries on after a change in your HRT, please see your GP. They may refer you for more tests, even if your womb lining on ultrasound is normal.

Contact numbers

If you have been referred to a Gynaecology Cancer Diagnostic Clinic, our contact details are below:

Maumbury Outpatients main reception: 01305 254803

Gynaecology nurse specialist: 01305 255719

You may be asked to leave a message – your call will be returned as soon as possible.

If you need to speak to someone about unscheduled bleeding on HRT but you have not been referred to a Gynaecology Cancer Diagnostic clinic, you should contact your GP.

Useful links

NHS UK – ultrasound scan: www.nhs.uk/conditions/ultrasound-scan/

YouTube – Transvaginal ultrasound exam: how it works: www.youtube.com/watch?v=6rJs-wyUaXQ
Although this video is about how a transvaginal scan can help with the diagnosis of ovarian cancer, rather than endometrial cancer, it does explain what happens when you have a transvaginal scan in a clear and reassuring way.

NHS UK – hysteroscopy – www.nhs.uk/conditions/hysteroscopy/

About this leaflet

Author: Mary Pickering and Hayley Yeoman, University Hospitals Dorset
Written: August 2024
Updated and approved: August 2024
Review date: August 2027
Edition: v1

If you have feedback regarding the accuracy of the information contained in this leaflet, or if you would like a list of references used to develop this leaflet, please email patientinformationleaflets@dchft.nhs.uk