Pelvic inflammatory disease (PID) is caused by an infection developing in the female upper genital tract.

In most cases, the condition is caused by a bacterial infection spreading from the vagina or cervix (the entrance to the womb) into the womb, fallopian tubes and ovaries.

PID is often caused by more than one type of bacterium and it can sometimes be difficult for doctors to pinpoint which are responsible. Therefore, a combination of antibiotics will be prescribed so that a variety of bacteria can be treated.

Sexually transmitted infections (STIs)

In about one in every four cases, PID is caused by a sexually transmitted infection (STI) such as chlamydia or gonorrhoea.

These bacteria usually only infect the cervix (neck of the womb), where they can be easily treated with a single dose of an antibiotic.  However, if they are not treated there is a risk that the bacteria could travel into the upper genital tract.

It is estimated that one in 10 women with untreated chlamydia may develop PID within a year.

Other causes

In many cases, the cause of the infection that leads to PID is unknown. Such cases may be due to normally harmless bacteria found in the vagina. These bacteria can sometimes get past the cervix and into the reproductive organs. Although harmless in the vagina, these types of bacteria can cause infection in other parts of the body.

Infection in this way is most likely to happen if you have had PID before, if there has been damage to the cervix following a miscarriage or childbirth, or if you have a procedure that involves opening the cervix, such as an abortion, inspection of the womb, or insertion of an intrauterine contraceptive device (coil).

Which areas can become infected?

If an infection spreads upwards from the vagina and cervix (entrance to the womb), it can cause inflammation of the:

• womb lining (endometrium)
• fallopian tubes
• tissue around the womb
• ovaries
• lining of the inside of the abdomen (peritoneum)

Pockets of infected fluid, called abscesses, can also develop in the ovaries and fallopian tubes.

Pelvic inflammatory disease (PID) can sometimes lead to serious and long-term problems, particularly if the condition is not treated promptly with antibiotics.

However, most women with PID who complete their course of antibiotics have no long-term problems.

Recurrent pelvic inflammatory disease

Some women will experience repeated episodes of PID. This is known as recurrent pelvic inflammatory disease.

The condition can return if the initial infection is not entirely cleared, often because the course of antibiotics was not completed, or because a sexual partner has not been tested and treated.

If an episode of PID damages the womb or fallopian tubes, it can become easier for bacteria to infect these areas in the future, making you more susceptible to developing the condition again.

Repeated episodes of PID are associated with an increased risk of infertility (see below).

Abscesses

PID can sometimes cause collections of infected fluid called abscesses to develop, most commonly in the fallopian tubes and ovaries.

Abscesses may be treated with antibiotics, but sometimes laparoscopic surgery (keyhole surgery) may be needed to drain the fluid away. The fluid can also sometimes be drained using a needle that’s guided into place using an ultrasound scan.

Long-term pelvic pain

Some women with PID develop long-term (chronic) pain around their pelvis and lower abdomen, which can be difficult to live with and can lead to further problems such as depression and difficulty sleeping (insomnia).

If you develop chronic pelvic pain, you may be given painkillers to help control your symptoms and tests to determine the cause may be carried out. If painkillers do not help control your pain, you may be referred to a pain management team or a specialist pelvic pain clinic.

Ectopic pregnancy

An ectopic pregnancy is when a fertilised egg implants itself outside of the womb, usually in one of the fallopian tubes.

If PID infects the fallopian tubes, it can scar the lining of the tubes, making it more difficult for eggs to pass through. If a fertilised egg gets stuck and begins to grow inside the tube, it can cause the tube to burst, which can sometimes lead to severe and life-threatening internal bleeding.

Therefore, medication to stop the egg growing or surgery to remove it may be recommended if you are diagnosed with an ectopic pregnancy.

Infertility

As well as increasing your risk of having an ectopic pregnancy, scarring or abscesses in the fallopian tubes can make it difficult for you to get pregnant if eggs cannot pass easily into the womb.

It’s estimated that about one in every 10 women with PID becomes infertile as a result of the condition, with the highest risk in women who had delayed treatment or repeated episodes of PID. However, a long term study in the US showed that women who had been successfully treated for PID had the same pregnancy rates as the rest of the population.

Blocked or damaged fallopian tubes can sometimes be treated with surgery, but if this is not possible and you want to have children, you may want to consider an assisted conception technique such as in-vitro fertilisation (IVF).

IVF involves surgically removing eggs from a woman’s ovaries and fertilising them with sperm in a laboratory, before planting the fertilised eggs are into the woman’s womb. This technique can help you get pregnant if you cannot have children naturally, but it’s important to be aware that it does not have a high success rate.

There is no single test for diagnosing pelvic inflammatory disease (PID). Your doctor will diagnose PID based on your symptoms and a gynaecological examination.

Your doctor will ask you about your medical and sexual history, before carrying out a pelvic examination to check for any tenderness and abnormal vaginal discharge. You may experience some discomfort during this examination, particularly if you do have PID.

Swabs will usually be taken from the inside of your vagina and cervix, which will be sent to a laboratory to look for signs of a bacterial infection and identify the bacteria responsible.

A positive test for chlamydia or gonorrhoea supports the diagnosis of PID, but most women have negative swabs and this does not rule out the diagnosis.

As PID can be difficult to diagnose, other tests may also be required to look for signs of infection or inflammation, or to rule out other possible causes of your symptoms. These tests may include:

• a urine or blood test
• a pregnancy test
• an ultrasound scan, which is usually carried out using a probe passed through the vagina (transvaginal ultrasound)

In some cases, laparoscopy (keyhole surgery) may be used to diagnose PID. A laparoscopy is a minor operation where two small cuts are made in the abdomen. A thin camera is inserted so that the doctor can look at your internal organs and, if necessary, take tissue samples. This is usually only done in more severe cases where there may be other possible causes of the symptoms, such as appendicitis.

Admission to hospital

You may be urgently admitted to hospital if:

• you are pregnant, especially if there is a chance you may have an ectopic pregnancy
• your symptoms are severe (such as nausea, vomiting and a high fever)
• you have signs of pelvic peritonitis (inflammation of the inside lining of the abdomen)
• an abscess is suspected
• you are unable to take oral antibiotics and need to be given them through a drip (intravenously)
• you may need emergency surgery, for example for appendicitis

Pelvic inflammatory disease (PID) is an infection of the female upper genital tract, including the womb, fallopian tubes and ovaries.

PID is a common condition, although it is not clear how many women are affected in the UK because it doesn’t always have any obvious symptoms.

PID mostly affects sexually active women from the age of 15 to 24.

Symptoms of pelvic inflammatory disease

PID can be difficult to recognise if the symptoms are mild, and some women don’t have any symptoms.

Most women have mild symptoms that may include one or more of the following:

• pain around the pelvis or lower abdomen (tummy)
• discomfort or pain during sex that is felt deep inside the pelvis
• pain during urination
• bleeding between periods and after sex
• heavy or painful periods
• unusual vaginal discharge, especially if it is yellow or green

A few women become very ill with:

• severe lower abdominal pain
• a high temperature (fever)
• nausea and vomiting

When to seek medical advice

It’s important to visit your GP or a sexual health clinic if you experience any of the above symptoms. If you have severe pain you should seek urgent medical attention from your GP or local emergency department. Delaying treatment for PID or having repeated episodes of PID can increase your risk of serious and long-term complications (see below).

There is no simple test to diagnose PID. Diagnosis is based on your symptoms and the finding of tenderness on a vaginal (internal) examination. Swabs will be taken from your vagina and cervix (the neck of the womb), but negative swabs do not exclude PID. 

Read more about diagnosing PID.

Causes of pelvic inflammatory disease

Most cases of PID are caused by a bacterial infection that has spread from the vagina or the cervix to the reproductive organs higher up.

Many different types of bacteria can cause PID. In about one in every four cases it is caused by a sexually transmitted infection (STI) such as chlamydia or gonorrhoea. In many other cases it is caused by bacteria that normally live in the vagina.

Read more about the causes of PID.

How pelvic inflammatory disease is treated

If diagnosed at an early stage, PID can be treated with a course of antibiotics, which usually lasts for 14 days. You will be given a mixture of antibiotics to cover the most likely infections, and often an injection as well as tablets.

It is important to complete the whole course and avoid having sexual intercourse during this time to help ensure the infection clears.

Your recent sexual partners will also need to be tested and treated to stop the infection recurring or being spread to others.

Read more about treating PID.

Complications of pelvic inflammatory disease

The fallopian tubes can become scarred and narrowed if they are affected by PID. This can make it difficult for eggs to pass from the ovaries into the womb, which can increase your chances of having an ectopic pregnancy (a pregnancy in the fallopian tubes instead of the womb) in the future, and can make some women infertile.

It’s estimated that around one in every 10 women with PID becomes infertile as a result of the condition, with the highest risk in women who have had delayed treatment or repeated episodes of PID. However, most women who are treated for PID will still be able to get pregnant without any problems.

Read more about the complications of PID.

Preventing pelvic inflammatory disease

You can help reduce your risk of PID by always using condoms with a new sexual partner until they have had a sexual health check. Chlamydia is very common in young men, and most do not have any symptoms.

If you are worried you may have an STI, visit your local GUM or sexual health clinic for advice. Find your local sexual health clinic.

If you need an invasive gynaecological procedure, such as insertion of a coil or an abortion, make sure that you have a check-up beforehand.

Read more advice about STIs. 

The Map of Medicine is used by doctors throughout the NHS to determine the best treatment options for their patients. NHS Choices offers everyone in England exclusive and free access to this cutting-edge internet resource, which lets you see exactly what your doctor sees.

The information in the Map has been approved by the UK’s leading clinical experts, is based on the best available clinical evidence, and is continually updated. To take advantage of this unique resource go to:

Map of Medicine: pelvic inflammatory disease

If it is diagnosed at an early stage, pelvic inflammatory disease (PID) can be treated easily and effectively with antibiotics prescribed by your GP or a doctor in a sexual health clinic.

However, if the condition is left untreated it can lead to more serious, long-term complications. See complications of pelvic inflammatory disease for more information about these and how they may be treated.

Antibiotics

Treatment with antibiotics needs to be started quickly, before the results of the swabs are available.

As PID is usually due to a mixture of different bacteria, even in cases where chlamydia or gonorrhoea is identified, you will be given a mixture of antibiotics to cover the most likely infections.

Antibiotics commonly prescribed to treat PID include ofloxacin, metronidazole, ceftriaxone and doxycycline.

You should tell your doctor if you think you may be pregnant before starting antibiotic treatment because some antibiotics should be avoided during pregnancy.

You will usually have to take the antibiotic tablets for 14 days, sometimes beginning with a single antibiotic injection. It is very important to complete the entire course of antibiotics, even if you are feeling better, to help ensure the infection is properly cleared.

In particularly severe cases of PID you may have to be admitted to hospital where you will receive antibiotics intravenously (through a drip in your arm).

If you have pain around your pelvis or tummy, you can take painkillers such as paracetamol or ibuprofen while you’re being treated with antibiotics.

Follow-up

In some cases, you may be advised to have a follow-up appointment three days after starting treatment so your doctor can check if the antibiotics are working.

If the antibiotics seem to be working, you may have another follow-up appointment at the end of the course of treatment to check if treatment has been successful.

If your symptoms haven’t started to improve within three days, you may be advised to attend hospital for further tests and treatment. If you have an intrauterine device (IUD) fitted, you may be advised to have it removed if your symptoms haven’t improved within a few days as it may be the cause of the infection.

Treating sexual partners

Any sexual partners you have been with in the six months before your symptoms started should be tested and treated to stop the infection recurring or being spread to others, even if no specific cause is identified.

PID can occur in long-standing relationships where neither partner has had sex with anyone else, and it is more likely to recur if both partners are not treated at the same time.

You should avoid having sex until both you and your partner have completed the course of treatment.

If you have not had a sexual partner in the previous six months, your most recent partner should be tested and treated. Your doctor or sexual health clinic can help you contact your previous partners and this can usually be done anonymously if you prefer.