Why are pregnant women at higher risk of flu complications?

During pregnancy the immune system is naturally suppressed, which means that pregnant women are more likely to develop complications.

However, the immune system is still working and the risk of complications is small.

Flu symptoms and complications

Most pregnant women will only have mild symptoms of flu and recover within a week. However, pregnant women are more likely to develop complications.

These complications can include:

  • pneumonia (an infection of the lungs)
  • difficulty breathing
  • dehydration

Complications such as these are more likely to happen from week 27 until the birth (third trimester) and up to two weeks after the birth.

If a pregnant woman develops a complication of flu, there’s a small chance that it will lead to early (premature) labour or miscarriage. It’s not known how likely these birth risks are to occur. Therefore, it's important to be well prepared and to take precautions against flu.

Preventing flu

If you’re pregnant, you can reduce your risk of infection by being vaccinated against flu.

Pregnant women are offered the flu vaccination on the NHS, as they have an increased risk of severe illness if they get flu.

Pregnant women benefit from the flu vaccine because it:

  • reduces their risk of serious complications such as pneumonia, particularly in the later stages of pregnancy
  • reduces the risk of miscarriage or having a baby born too soon or with a low birth weight, because of flu
  • will help to protect their baby, who will continue to have some immunity to flu during the first few months of its life


You should also:

  • put used tissues in a bin as soon as possible
  • wash your hands regularly with soap and water
  • clean surfaces regularly to get rid of germs

Read more about getting the flu jab in pregnancy

Further information: 

Page last reviewed: 21/01/2015

Next review due: 20/01/2017

More about: h1n1 flu (swine flu)