Can the flu jab cause miscarriage?

Getting the flu vaccine is safe and will help protect you and your baby. There is no evidence to show that the flu vaccine can cause miscarriage.

Why has the flu jab been linked to miscarriage?

In 2017, a research study in the US suggested a possible link between the flu vaccine and miscarriage. This had a lot of media interest, which led people to ask if having the flu vaccine in pregnancy is safe for their baby.

It’s completely understandable to worry about vaccine safety when you’re pregnant. But this small piece of research did not show that the flu vaccine causes miscarriage.

There is a lot more scientific evidence that shows that the flu vaccine is safe to have at any time of pregnancy. It’s also safe to have the vaccine if you’re breastfeeding.

The study in question looked at women who had been given a swine flu vaccine between 2010 and 2012 and whether this increased their risk of miscarriage. These are the reasons the results from this study were too weak:

  • The results came from an analysis after the investigation took place. Flu and miscarriage wasn’t the original subject of the research. This means that the right controls for the study weren’t in place.
  • The women studied were only matched for the time of their last period, the hospital they were in and their age. The study didn’t take into account other known factors that can cause miscarriage, such as diabetes, BMI, previous miscarriage history and smoking.
  • The study looked at 485 pairs of women. For a reliable result, you need at least 500 pairs of women.
  • On top of this, the conclusion that the vaccine is linked to miscarriage only came from a sub-group of these 485 paired women, making the pool of women they were testing from even smaller.
  • In the study, the link was shown in one season, but not in the season the year after, which makes the results inconclusive. To see if there really is a link, you would need to conduct the study over a much longer period of time.

Getting the flu is harmful in pregnancy and increases the risk of problems for the baby. Public health authorities in the US and the UK still recommend that every pregnant woman has the flu jab to reduce these risks. 

What are the risks of flu in pregnancy?

You’re more likely to get the flu when you’re pregnant because your immune system is weaker. Your risk of developing complications from flu is also higher, which can make you very ill. Bronchitis (a chest infection), is a common complication that can develop into pneumonia.

Getting the flu during pregnancy can also cause premature birth, low birthweight and even stillbirth.

The flu vaccine will help protect you and your baby during your pregnancy. It can also protect your baby for the first few months of life.

When should I have the flu jab?

The flu vaccine is normally available from September until January or February each year.

You can have the flu vaccine at any stage of your pregnancy. Try to have the vaccine when it becomes first becomes available so that you’re protected in time for winter. But don’t worry if you find out you’re pregnant during flu season, just have the vaccine as soon as you can.

Does the flu jab give me a mild dose of the flu?

No. The vaccine doesn’t contain any live viruses, so it can’t give you the flu.

How do I get the flu vaccine?

The flu vaccine is free for pregnant women. Contact your GP surgery to make an appointment. Your midwife may also be able to give you a flu vaccine at the antenatal  clinic. Your local pharmacy may also be able to do it.

What if I get the flu?

Having the flu vaccine doesn’t guarantee you won’t catch the flu. However, if you do get it, there is some medicine you can take that may reduce your risk of complications. See your GP if you think you’re getting ill.  

Flu symptoms come on very quickly and can include:

  • a sudden fever – a temperature of 38C or above
  • an aching body
  • feeling tired or exhausted
  • a dry cough
  • a sore throat
  • a headache
  • difficulty sleeping
  • loss of appetite
  • diarrhoea or tummy pain
  • nausea and being sick.

Don’t take any over-the-counter decongestants to treat the flu or if you have a cold. It’s not clear whether it’s safe to take these if you’re pregnant or breastfeeding. Your GP will be able to advise you how to treat your symptoms.

Find out more about what medications you can take in pregnancy.

If you’re still concerned

Research into possible causes for pregnancy loss is important and helps us find ways to have a healthier and safer pregnancy. But sometimes the way this research is reported in the media or discussed online can be misleading.

This can be very difficult if you’re pregnant or have lost a baby before. Talk to your midwife if you see, hear or read about anything pregnancy-related that worries you. You can also get in touch with us at Tommy’s.

NHS Choices. The flu jab in pregnancy. (Page last reviewed: 25/08/2016. Next review due: 31/08/2019)

NHS Choices. Flu.  (Page last reviewed: 12/1/2017. Next review due: 12/12/2020)

NHS Choices. Decongestants.  (Page last reviewed: 03/03/2016. Next review due: 01/03/2019)

Review dates
Reviewed: 30 January 2019
Next review: 30 January 2022

This content is currently being reviewed by our team. Updated information will be coming soon.