It is usually caused by an infection that spreads up from the neck of the womb (the cervix). In around 25% of cases it is caused by a sexually transmitted infection such as chlamydia or gonorrhoea. However, it can also come from elsewhere, such as acute appendicitis or from surgery in that area.
If left untreated the pain will continue and the inflammation will not go away. PID can also put you at risk of infertility (not being able to have children).
The most common symptom is lower (below the belly button) abdominal pain (usually on both sides), similar to period pain. Pain can vary from very mild to severe, but usually gets worse during and after sex. Sometimes it is accompanied by abnormal bleeding and a change in vaginal discharge.
On rare occasions you can become very ill, with severe lower abdominal pain, a high temperature, nausea and vomiting.
If you think you have PID it’s important that you tell your GP or visit a sexual health clinic. Most women are diagnosed following an examination by a doctor or a nurse. On very rare occasions a small operation, known as a laparoscopy, may be needed to look inside. Swabs are taken to look for common infections such as chlamydia and gonorrhoea.
PID is usually treated with a mixture of antibiotics to cover the most likely infections. Rest and ordinary painkillers can be helpful. If the symptoms are severe or get worse you may need to go into hospital.
To avoid catching PID again, it is important that your partner(s) are also tested and treated. You should also not have sex (even with a condom) until you and your partner have finished treatment.