Post-coital bleeding

Also known as bleeding after sex

Post-coital bleeding is when a woman experiences vaginal bleeding after having sex. If you experience vaginal bleeding and it is not due to your period, see your doctor. Normally it is nothing to worry about but, in some cases, it could be a sign of something more serious.

What is post-coital bleeding?

Post-coital bleeding is vaginal bleeding that occurs within 24 hours after sexual intercourse.

Normally a woman should only have vaginal bleeding when she has a period, but if a woman has irregular periods she may not be sure if the bleeding is normal or not. If you are not sure if your bleeding is part of a period, see your GP to discuss this. 

Heavy bleeding immediately after sex is not normal – seek urgent medical help

Where does post-coital bleeding come from?

A woman's reproductive system can be divided into the upper part and lower parts:

  • The upper part includes the body of the uterus, the fallopian tubes and the ovaries. Bleeding during a woman's period occurs when the lining of the uterus breaks down as part of a normal monthly cycle.
  • The lower part of a woman’s reproductive system is the neck of the womb (or cervix), the vagina and the outer part which is called the vulva and labia. 

It is the lower parts which are usually involved in post-coital bleeding. 

What are the causes of post-coital bleeding?

The most common causes of post-coital bleeding include:

  • Cervical polyps – small growths caused when cells multiply abnormally. In rare situations these can develop into cancer. They can easily be removed at the time of a smear test.
  • Cervical ectropion – when cervical cells grow outside the cervix, where they can be damaged during sex.
  • Vaginal thrush a common yeast infection that can occasionally cause bleeding along with other common symptoms such as pain, itching and vaginal discharge.
  • The contraceptive pill or injectioncontraceptives can affect the lining of the cervix and make it extra-sensitive, especially when you first start on them.
  • Having sex – occasionally, sex can cause bleeding from a woman's vagina or vulva, especially in women with a condition called atrophic vaginitis where the lining of the vagina becomes thinner.

Less common but more serious causes include:

  • Cervical cancer – this a serious condition, however, if treated early it can be cured completely. This cancer can be identified before it becomes a serious threat by having a smear test. Remember that no test is perfect, so even if you have had a recent smear test, you should still see your GP if you have post-coital bleeding.
  • Cervical infections – such as chlamydia and gonorrhoea. These infections can cause serious problems and need to be treated.
  • Pregnancy – bleeding in early pregnancy is common, but needs to be checked out by a doctor. Early pregnancy bleeding can occur with an ectopic pregnancy, which occurs when the pregnancy is growing in the fallopian tube. This is potentially very dangerous.

In girls who have not started having periods, any vaginal bleeding is not normal. See your doctor for a check-up and advice. 

Read more about these causes of post-coital bleeding

How is post-coital bleeding diagnosed?

To find out the cause of the bleeding, your GP will need to ask you some personal questions about your sexual activity. These questions can be a bit embarrassing but remember your GP deals with this kind of thing all the time. The more information you can give the easier it will be for them to find out what's going on. 

Your GP will also need to find out about:

  • what contraception you are using
  • any other medications you are on
  • when you last had a cervical smear.

If you are not seeing your regular GP it can be really helpful if you take along your medications such as “the pill” if you are using it.

Tests and procedures

There are some common tests and procedures which your doctor may also require, such as:

  • A urine sample to check for pregnancy or urine infection.
  • A vaginal examination to look for causes of bleeding in your vagina or cervix. This examination is the same as having a smear test. A smear might be repeated and tests for infection can be done at the same time.
  • Occasionally your GP may also do a test called a pipelle. This is done at the same time as a smear test, but using a very thin plastic tube to collect a sample of the lining of the uterus. The GP will want to know if you are pregnant before this test.
  • An ultrasound scan, especially if: your pregnancy test is positive; the examination suggests there is a problem with your uterus or ovaries; you are over 45 years old or if there is a family history of certain types of cancer.

What is the treatment for post-coital bleeding?

Treatment for post-coital bleeding will depend on what the cause is. Your doctor will advise you on the best course of action once a diagnosis has been made. 

References

Wan YL, Edmondson RJ, Crosbie EJ. 2015 Intermenstrual and Postcoital Bleeding. Obstetrics, Gynaecology And Reproductive Medicine 25:4 107-12

Credits: Dr Jeremy Tuohy, Obstetrician & Researcher, University of Auckland. Last reviewed: 28 Nov 2016