Most pregnant women who get slapped cheek syndrome have healthy babies.
But depending on what stage of pregnancy you're at, there's a small risk of miscarriage or complications for your unborn baby.
If you're pregnant and have been exposed to the virus, you should see your GP or midwife, or call NHS 111.
What is slapped cheek syndrome?
Slapped cheek syndrome, also known as fifth disease, is caused by a virus called parvovirus B19.
The main symptom is a bright red rash on both cheeks, although adults don't always get the rash.
After 1 to 3 days a light pink rash may appear on your body, which can be itchy.
In about 20 to 30% of infections, there are no symptoms.
Slapped cheek syndrome usually affects children. It's thought that once you have been infected, you're immune for the rest of your life.
Studies have shown that around 60% of adults in the UK have antibodies to parvovirus B19.
It's difficult to avoid contact with people who have slapped cheek syndrome because they may have no symptoms.
Once the rash appears, the person is no longer contagious.
Read more about slapped cheek syndrome.
Complications during pregnancy
If you get slapped cheek syndrome during your first 20 weeks of pregnancy, there's an increased risk of miscarriage.
If you become infected during weeks 9 to 20 of pregnancy, there's also a small risk that the baby will develop foetal hydrops (also known as hydrops fetalis).
Some babies recover from foetal hydrops, but it can be fatal.
There's no evidence that having slapped cheek syndrome during pregnancy causes birth defects or development problems later in childhood.
When to get advice
See your GP or midwife as soon as possible if you're pregnant and you think you have come into contact with someone with slapped cheek syndrome. You should do this whether you develop a rash or not.
There's no routine screening test for slapped cheek syndrome in pregnancy. You'll have a blood test.
If you test positive for the virus in the first 20 weeks of pregnancy, you'll be offered ultrasound scans throughout your pregnancy to monitor your baby.
If your baby develops foetal hydrops, they may need a blood transfusion while still in the womb.
Read more about infections in pregnancy.
Page last reviewed: 15 October 2018
Next review due: 15 October 2021