Loop diathermy after a colposcopy

A loop diathermy is used to treat an abnormality (something that is not normal) on the cervix. It involves taking a biopsy of the cervix (neck of the womb) using a thin loop of electrified wire to remove the abnormal cells. This procedure is also known as a large loop excision of the transformation zone (LLETZ).

We are doing the procedure to remove the area of abnormal cells which have been identified on your cervix during your colposcopy (detailed examination of your cervix).

The procedure is usually done under local anaesthetic (where a medicine is used to numb the cervix). Sometimes we need to do the procedure when the patient is under a general anaesthetic (asleep for the whole procedure).

You can read more about having an anaesthetic.

Risks of having a loop diathermy

It is important to remember that we are doing the treatment to your cervix to help prevent possible cervical cancer from developing. There are risks with any procedure, the main risks of having a loop diathermy are:


It is normal to have some light bleeding and discharge for up to 4 weeks after the treatment. At first, we would expect you to have a mucky-looking discharge (brown from the iodine used) with a few spots of blood. This might then become a very watery discharge. We would not expect you to have heavy bleeding.


If you have a vaginal discharge which has an offensive (bad) smell, a fever or severe ongoing lower abdominal (tummy) pain, it might be a sign that you have an infection. Please go to your GP, who might prescribe you antibiotics.

If you are still bleeding after 4 weeks, please contact the colposcopy unit as this could be a sign of infection. We might advise you to go to your GP for an examination of your cervix.

Premature delivery

The treatment should not affect your ability to become pregnant. However, treatment might weaken the cervix and may slightly increase the risk of premature delivery. If you get pregnant after having this treatment, we advise you to tell your GP and midwife that you have had a loop diathermy.

Narrowing (stenosis) of the cervical os (the small opening of the cervix)

After loop diathermy to your cervix there is a small risk (less than 2 out of every 100 cases) that the cervical os will close over. You can help prevent this by allowing your period to come as normal after the procedure. If you take a 21-day contraceptive pill, this means that you should not run 2 packs together. Instead, you should make sure you leave a week (the 7-day break) between finishing one pack and starting the next.

Coils (IUCD or IUD) or Mirena (IUS)

If you have a coil or Mirena fitted, the clinician might take it out when you have the treatment. A coil can usually be refitted 4 weeks after your treatment, but please wait for your results letter before arranging to have this done. The best time to fit your new coil will have to be agreed with your GP or family planning clinic.

You should use an additional method of contraception (such as condoms) as well as the coil, or not have sex, for 7 days before your planned procedure.


Having a loop diathermy should not affect your ability to become pregnant.

If you are pregnant 

It is not possible for us to do surgery on your cervix if you are pregnant. To make sure that you are not pregnant on the day of your surgery, we ask that you have protected sex for 7 days before your operation date. We will also ask you about dates of your last period. If there is any chance you are pregnant, please tell the doctor or nurse. We might ask you for a sample of pee (urine) to do a pregnancy test. 

If you are pregnant when you are due to have the procedure, we will delay your treatment until after you have had your baby. You should let us know your expected date of delivery when you come to see us.

The doctor or nurse looking after you might want to monitor the abnormal cells throughout your pregnancy. They will do this by asking you to come for another colposcopy while you are pregnant, but this does not harm your baby.

You will be asked to come back to the colposcopy unit 12 weeks after giving birth, so that we can have another look at your cervix. We might also carry out the treatment at this time.

Other treatment options

Your doctor or nurse will have recommended loop diathermy because they believe this is the best way to get an accurate diagnosis of the stage of your cervical abnormality. If you have any questions about why we have recommended this procedure for you, please contact us.

Asking for your permission (consent)

We want to involve you in all the decisions about your care and treatment. If you decide to go ahead under local anaesthetic, you will be asked to agree verbally (spoken) to the procedure.

If you decide to have the procedure under general anaesthetic you will be asked to sign a consent form. This states that you understand what it involves and you agree to have the treatment.

Remember, it is your decision. You can change your mind at any time, (as long as this is before the procedure is started), even if you have signed the consent form. Let staff know immediately if you change your mind. Your wishes will be respected at all times. If you would like more information about our consent process, please speak to a member of staff caring for you.

You can read more about giving your consent.

Going on holiday

If you are planning on going abroad and we have sent you an appointment for treatment, please call us to let us know. We would normally suggest that you do not travel abroad for at least 2 weeks after the treatment. This is because of the risk of bleeding and other complications.

Preparing for a loop diathermy

If you are having local anaesthetic

If you are having a local anaesthetic, you can continue as normal before the procedure. It is important that you eat and drink before the procedure and do not starve yourself.

It can be helpful to bring someone with you so that they can take you home after the procedure, but it is not essential.

If you are having a general anaesthetic

If you are having a general anaesthetic, we will give you instructions in your admission letter about when you need to stop eating and drinking certain liquids (fasting) depending on the time of your operation. Fasting means that you cannot eat or drink anything (except water) for 6 hours before surgery. We will give you clear instructions on when to start fasting. It is important to follow these instructions. If there is food or liquid in your stomach during the anaesthetic it could come up to the back of your throat and damage your lungs. 

You can read more about having local and general anaesthetic.

Having a loop diathermy

If you are having local anaesthetic

You will be seen in the same department where you had previous colposcopy appointments. This is the colposcopy unit which is located in the gynaecology outpatients department (McNair Centre, Guy’s Hospital).

You will have a consultation with the colposcopist. You will be taken to the examination area where you will be asked to undress from the waist down (a loose skirt does not need to be removed). The nurse who will be looking after you and assisting the colposcopist will help you to get into the right position on the examination couch.

If you are having general anaesthetic

You will have an appointment in the colposcopy unit or McNair Centre at Guy’s Hospital to discuss the operation with a doctor. You will be asked to sign your consent form. You will also be seen in the McNair Centre for your pre-assessment appointment. You will have your actual treatment done in Lambeth Theatres (day surgery) at St Thomas’ Hospital. 

The consultant, or one of their team, will talk to you before your operation and they will recheck the consent form with you. The nursing team will look after you. You will be asked to undress completely and put on a hospital gown. You will be taken to the operating theatre where your general anaesthetic will be given and where you will be treated while you are asleep.

During the procedure

The procedure usually takes 15 to 20 minutes. During the examination an instrument called a speculum is inserted into your vagina to hold back the vaginal walls so the clinician can see your cervix. The colposcopist then uses the colposcope to examine your cervix. They might apply some liquid to the cervix to show any abnormal-looking areas. The area is then numbed if you are having the procedure under local anaesthetic (if you are having a general anaesthetic you will already be asleep).

When the local anaesthetic has taken effect, the colposcopist will proceed with the treatment. The area of abnormality is removed using the thin loop of electrified wire, which also helps to stop any bleeding caused by removing the tissue. The area is then cauterised (sealed using a hot implement) to prevent further bleeding.

After the procedure, the speculum will be taken out and you will be asked to rest on the examination couch for a few minutes. The nurse will tell you when to get up and dressed. When you are dressed you will go back to see the colposcopist who will talk to you about the procedure.


You should not feel any pain during the procedure. If you are having a general anaesthetic you will be asleep. Local anaesthetic is given before the treatment, so you should not feel any pain during the procedure, but you might feel some pressure on your cervix.

It is unusual to feel discomfort after the treatment. You might get a mild period-like pain. If this happens you should take your regular painkillers.

After the loop diathermy

If you had local anaesthetic

We ask you to stay in the department for about 20 minutes after the procedure. During this time a nurse will check on you, go through the aftercare instructions, and answer any questions you have. We advise that you bring someone with you, so that they can take you home after the procedure. You can eat and drink as normal.

If you had general anaesthetic

You will need to stay in the day surgery unit for at least 2 hours after the procedure. You must have someone who can take you home after a general anaesthetic, and a responsible adult (over 18 years of age) needs to stay with you overnight.

You can read more about about having surgery at our hospitals.

After you leave hospital

We advise that you go home after the procedure and rest for the remainder of the day. If you have had a local anaesthetic you should be able to go to work the next day. If your appointment is late in the afternoon, you might want to book the next day off work.

If you have had a general anaesthetic, you should rest on the day of your operation. You do not need to stay in bed the next day, but we would advise that you have a restful day. Ideally, we would recommend that you have someone staying with you for the first 24 hours.

With local and general anaesthetics, we recommend that you return to work depending on how you feel and how physical your job is. You should be able to self-certify your absence from work for 7 days. Please avoid any heavy lifting (at home or at work) for the next 2 weeks.

In the first 48 hours after surgery we advise you:

  • do not drive a car or ride a bike
  • do not operate machinery
  • do not cook, use sharp objects or pour hot liquids
  • do not drink alcohol
  • do not smoke
  • do not take sleeping tablets
  • do not make important decisions or sign contracts

We recommend that you avoid swimming until the vaginal discharge has stopped, ideally for at least 4 weeks. Please do not go to a gym or do any strenuous exercise, for 2 weeks after your procedure. After this time you can slowly build up to your usual fitness routine. If you start to bleed during or after a gym session, do not go again for a week.

When you get your menstrual period, only use sanitary towels. Do not use tampons or have sex for 4 weeks after your treatment. This allows time for the cervix to heal and reduces the risk of infection and bleeding.

You can bathe as normal after your treatment. We would advise you to shower where possible, however if you do not have access to a shower, please have a warm bath (not hot).

Go to your nearest emergency department (A&E) if:

  • you have heavy bleeding, which is heavier than your normal period, or if you are passing blood clots.

Follow-up appointments

It is very important that you have your first cervical screening test (smear test) 6 months after your treatment. This is the human papilloma virus (HPV) ‘test of cure’, where we check that the HPV is no longer active, therefore not detected. If the HPV is still detected, the laboratory will also check whether there are any abnormal changes to the cells. More information on these tests will be given to you in the clinic after your procedure.

You are usually discharged after your LLETZ and told to have your cervical screening test of cure at your GP surgery 6 months after your treatment. We will tell you where you need to have your next cervical cytology test taken in your results letter. If you do not get your results letter within 8 weeks after your treatment, please ring the colposcopy unit.

More information

We have listed some useful websites which we believe have the most detailed information and we hope will answer more of your questions. It does not mean that you have cancer. 

Macmillan cancer support Support line, phone: 0808 808 00 00
Support and information about all types of cancers

Cancer Research UK, Support line, phone: 0808 800 4040  
Includes information about abnormal cervical cells, and types of treatment. 

Cervical cancer screening
Information from Gov.uk about the UK's cervical cancer screening programme

British society for colposcopy and cervical pathology
Information about screening and treatment

Resource number 2503/VER8
Date published: November 2023
Review date: November 2025

Contact us

If you have any questions, please contact the Colposcopy unit

phone: 020 7188 3691, Monday to Friday, 9am to 5pm.

Appointments and cancellations
email: [email protected]@gstt.nhs.uk

Clinical questions 
email: [email protected]

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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