Information alert

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This is information about a treatment for uterine fibroids known as ‘transcervical ultrasound-guided radiofrequency ablation’. You may also hear it called by the Manufacturer’s name ‘Sonata®’ for short.

Fibroids are benign (non-cancerous) muscle growths of the uterus (womb). They can vary in size and number. About one in every three women have fibroids.

Often fibroids cause no symptoms at all, and many women will not know that they have them. However, they can cause your periods to be heavy. It is uncommon to feel pain from fibroids, but when they are large they can cause a feeling of pressure, or can push on the bladder and cause urinary symptoms.

Most fibroids do not need treatment. Where treatment is needed, there may be several different options depending on the number and size of the fibroids, where they are located within the womb, and what symptoms they are causing.

Sonata® is a new treatment for fibroids being used at UCLH. It has been used for women in the United States and some hospitals in Europe since 2015. In 2021, it was approved for use in the UK by the National Institute for Health and Care Excellence (NICE).

Over nine out of every 10 patients had an overall improvement in symptoms after 12 months (about one in 100 had worsened symptoms).

Nine in every 10 patients reported that their period blood loss was reduced after three months.

A year after the procedure about seven in every 10 patients were bleeding less than half the amount they were before the procedure.

About nine in every 10 patients were satisfied with the treatment after 12 months.

About eight in every 10 patients would definitely recommend the procedure to someone else (three in 100 said they would probably not recommend it).

When the procedure is first introduced to our unit, it will be performed by an experienced consultant who has been trained in the use of the device, supported by a clinical specialist who works for the company that has developed Sonata.

All treatments and procedures have risks, and we will talk to you about the risks of Sonata® so you can make an informed decision about whether to proceed.


Problems that may happen straight away

You may feel pain during the treatment if you have it carried out under local anaesthetic. You may also have discomfort or some pain after the treatment. Usually this settles with simple pain killers.

Seven out of every 10 women report the treatment to be very or quite tolerable (two in 100 report it as not tolerable).


Problems that may happen later

You may have vaginal bleeding for some days after the procedure.

After you go home you may also notice:

  • fibroid sloughing (bits of fibroid tissue, which might look ‘fleshy’ being passed through the vagina) (three in every 10 women)
  • crampy like abdominal pain (eight out of every 100 women)
  • vaginal discharge (six out of every 100 women).

Less commonly you may develop a mild infection in the vagina, causing fever or smelly discharge, or a urinary tract infection. If this occurs, or if you have bleeding lasting for longer than two weeks after the procedure, please contact your doctor or the gynaecology department.


Problems that are rare, but serious

There have been no serious safety concerns identified with the Sonata device or procedure.

If you choose not to have Sonata® treatment then your doctor will discuss whether you wish to have either:

  • No treatment – in this case your symptoms may stay the same, or worsen.


  • An alternative treatment - the alternatives depend on the number and location of your fibroids, your symptoms, and whether you would like to become pregnant in the future.

Medical treatment
This may include non-hormonal tablets such as tranexamic acid or hormonal treatment such as a contraceptive pill (combined or progesterone only).

Surgical treatment
Transcervical resection of a fibroid is suitable for fibroids inside the uterus cavity. Laparoscopic (keyhole) myomectomy (fibroid removal) is suitable for fibroids outside the uterus. Open myomectomy is suitable when the fibroids are very large in size or number.
Some patients choose to have a hysterectomy (removal of the whole uterus) if other treatments have not worked.

Uterine artery embolisation is a technique where tiny particles are injected into the blood vessels to stop the blood supply to the fibroids.

You should make sure that you have some simple painkillers, like paracetamol and ibubrofen if you are able to take these, at home for after the procedure.

On the day of the procedure, you should wear comfortable underwear and bring spare sanitary pads and something to read.

You will be advised not to eat and drink for a number of hours before your procedure: the pre-assessment team will contact you before the procedure to explain this in detail. You should take any regular medications on the morning of the procedure.

The procedure itself typically takes between 30 and 60 minutes, but if you have had a general anaesthetic, then you may be in the recovery area for some time as you wake up from the anaesthetic.

You will be able to go home as soon as you feel well and you will need to have arranged for an adult to escort you home after the procedure.

We want to involve you in all the decisions about your care and treatment. If you decide to go ahead with treatment, by law we must ask for your consent and will ask you to sign a consent form. This confirms that you wish to have the procedure and understand what it involves.

If you are unsure about any aspect of your proposed treatment, please don’t hesitate to speak with a senior member of staff again.

We plan to carry out most procedures at UCLH as an ‘awake’ procedure with local anaesthetic. For some women, we will recommend you are asleep under general anaesthesia.

Sonata® does not involve cuts in the tummy or any stitches.

Instead it involves passing the Sonata® device through the cervix (neck of the uterus). The device has two parts: the first is a thin camera (ultrasound scanner) which allows the surgeon to see and guide the procedure; and the second is a specially designed probe that uses radiofrequency energy (a type of heat generation) to treat the fibroid. The energy is very focused and so there is no damage to the uterus around the fibroid.

Sonata treatment.jpg

If you have had a general anaesthetic, then you may feel drowsy or nauseated for a few hours. You should avoid driving for 24 hours.

After the procedure, you will probably have some vaginal bleeding. If your bleeding is very heavy and worrying you should go to the nearest Emergency Department.

Cramping tummy pain is common and you should use simple, pain killers such as paracetamol and ibuprofen (if you are able to take these). You are likely to be able to return to normal activities within a few days (average is four days).

You can have sex once any initial pain and bleeding has settled. You should continue to use your normal contraception.

Your next period will probably occur at the expected time, but may be early or late. You may not notice an improvement in your symptoms for a few months, so do not worry if your periods or pressure symptoms are not immediately better.

If you have a non-urgent query please call our team on 020 3447 9411 during working hours, who can pass a message to your doctor.

We will arrange to see you three months and 12 months after the Sonata® procedure. You should contact us on the telephone number below if you have concerns between those appointments.

The manufacturer of the Sonata® device provides patient information on their UK website:

UCLH cannot accept responsibility for information provided by other organisations.

Gynaecology Outpatient Diagnostic and Treatment Unit:

You will be given details of where to attend for your procedure depending on whether this will be under general or local anaesthetic.

The Gynaecology Outpatient Diagnostic and Treatment Unit is located in the Elizabeth Garrett Anderson Building (Lower Ground Floor, Clinic three).

















Page last updated: 03 May 2024