Unscheduled vaginal bleeding while using HRT is common and is usually caused by the HRT.
As the cause of your bleeding is likely to be the HRT, your GP may recommend stopping your HRT for a short period to see if your bleeding improves.
If you still have a uterus (womb) you will have been prescribed HRT containing two hormones – oestrogen and progesterone.
If you have been prescribed progesterone it is very important to take this as directed. This is to protect the lining of your womb (endometrium) from abnormal or cancerous changes.
Your progesterone will be prescribed to be taken every day (continuous combined HRT) or for 12 to 14 days out of every 28 days (sequential combined HRT).
Continuous Combined HRT (both oestrogen and progesterone are taken or used every day)
- Progesterone should be taken every day
- Normally prescribed if your last period was over 12 months ago or if you are not bleeding because you are taking progesterone only contraception (such as the ‘mini-pill or have a Mirena coil)
- There is usually no vaginal bleeding expected when taking it
- All vaginal bleeding should stop after 6 months or less
Sequential Combined HRT (oestrogen is taken or used every day and progesterone is taken for 12-14 days out of every 28 days)
- Progesterone should be taken for 12 to 14 days out of every 28 day cycle.
- Normally prescribed if you have had a period within the last 12 months.
- Usually patients will have a monthly vaginal bleeding lasting 3 – 7 days
- Some patients don’t have any vaginal bleeding and this is nothing to worry about as long as they are taking the progesterone as prescribed. If you are pre-menopausal and you stop bleeding while on sequential combined HRT, check for pregnancy.
Unscheduled bleeding (bleeding outside of what is expected)
- Common when taking HRT and is usually caused by the hormones in HRT.
- It can also be caused by changes to the dose or type of HRT.
- Rarely, it can be a sign of a more serious problem such as cancer in less than 1 in 200 (<0.5%) of those who experience bleeding on HRT.
What to do if there is unscheduled bleeding while on HRT
- After 3 months of starting HRT, make an appointment with your GP
- Your GP will ask questions about your symptoms and your HRT use, offer to do an internal examination to look for a cause of your bleeding and may suggest a change to your HRT to try to improve your bleeding.
- If your unscheduled or abnormal bleeding persists for 6 months or more then your GP may want to do further tests such as an ultrasound scan and they may refer you to the hospital gynaecology team.
Some women have a greater risk of developing endometrial (lining of the womb) cancer. These risks include:
- Being very overweight (BMI greater than 40)
- Having a genetic disorder (Lynch/Cowden syndrome)
- Having a womb but not taking progesterone treatment for 6 months or more
- Using sequential combined HRT for more than 5 years.
- Being diabetic
You should inform your GP immediately if you have
- Vaginal bleeding after sex (also known as postcoital bleeding)
- Very heavy or prolonged vaginal bleeding when taking HRT
- Unscheduled or abnormal vaginal bleeding after taking HRT for 3 months or more.
- Any vaginal bleeding if you no longer have a uterus
- You think you may be at increased risk of developing endometrial cancer.