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Infections during pregnancy

It’s totally natural to worry about how infections like UTIs, flu, chickenpox and rubella might affect your baby in pregnancy. Here’s what you should know.

If you’re wondering why you’re susceptible to every cold going while you’re pregnant, it’s because your immune system can be less effective against infections. Your immune system during pregnancy is not supressed exactly but is unique and modulated, possibly to prevent your body rejecting your baby (Mor and Cardenas, 2010).

Infections to watch out for when you’re pregnant include:

Urinary tract infections

Urinary tract infections (UTIs) are caused by bacteria in your wee.

If you get a UTI when you’re pregnant, it can be serious for you and your baby (Vazquez and Abalos, 2011; Schneeberger et al, 2015).

UTIs can be more common when you’re pregnant because it’s harder during pregnancy to completely empty your bladder (as you’ll know when you’re in the loo at 3am). That means the wee left behind can become infected. Sometimes infections can backtrack to the kidneys too, leaving you in pain and nauseous (Vazquez and Abalos, 2011).


Chickenpox during pregnancy can be dangerous for both you and your baby. So if you get it, call your GP straight away (NHS Choices, 2018).

You probably had it as a child so are immune. If you didn’t, or if you aren’t sure, and you come into contact with someone who has it, get checked out ASAP (NHS Choices, 2018).

German measles or rubella

The MMR (measles, mumps and rubella) vaccine means that rubella or German measles is rare in the UK. But if you get it in the first four months of pregnancy, it can lead to serious problems (NHS Choices, 2018).

Contact your GP or midwife if:

  • you come into contact with someone who has rubella or a rubella-like rash
  • you have a rash
  • you have symptoms of rubella.

You’ll also be offered screening for rubella in pregnancy (NICE, 2017).


Flu can have serious complications especially during the later stages of pregnancy So whatever stage of pregnancy you’re at, book in for the flu jab.

The flu vaccine is totally safe to have when you’re pregnant (NHS Choices, 2016a).

If you don’t get a flu vaccine, you could develop complications like chest infections and it may affect your baby (NHS Choices, 2016a).

Sepsis (maternal sepsis)

Maternal sepsis is caused by your body’s reaction to an infection and can lead to multiple organ failure. It can even be fatal. Find out more about symptoms to watch out for here.

Sepsis is the leading cause of deaths in women giving birth in the UK, so it’s good to be aware of it. A blood culture test will confirm the diagnosis (RCOG, 2012).

Whooping cough

Whooping cough is a bacterial infection of the lungs and airways that is super contagious through sneezes and coughs. Whooping cough causes repeated coughing bouts and can be harmful to babies and young children. Symptoms include:

  • colds
  • runny nose
  • red and watery eyes
  • sore throat
  • slightly raised temperature.

Coughing bouts start about a week after you get these initial symptoms.

Three routine vaccinations for whooping cough can protect babies and children:

  • Whooping cough vaccine  in pregnancy – to protect your baby during their first few weeks of life.
  • 5-in-1 vaccine – offered to babies at 8, 12 and 16 weeks.
  • 4-in-1 pre-school booster – offered to children by 3 years and 4 months.

(NHS Choices, 2016b)

HIV in pregnancy

You’ll be offered an HIV test as part of your standard antenatal care. If you’re HIV positive but in good health, pregnancy shouldn’t affect you.

However, you can pass HIV to your baby during pregnancy, birth or breastfeeding. Speak to your doctor about treatments that reduce the risk of passing on HIV to your baby (NHS Choices, 2018).

Hepatitis B

Hepatitis B is caused by a virus that infects the liver and is transmitted through sex or by direct contact with infected blood.

If you’re hepatitis B positive and pregnant, you can pass the infection to your baby at birth.

You’ll be offered a hep B test as part of your standard antenatal care. If you’re positive, your baby will be given a vaccine at birth to prevent infection and liver disease later on in life (NHS Choices, 2018).

Herpes in pregnancy

Genital herpes infection is a sexually transmitted infection passed through vaginal, anal and oral sex. It can be dangerous for a newborn baby (NHS Choices, 2018).

If your first infection happens when you’re pregnant, you can get treatment. If it’s near the end, you’ll probably be advised to have a caesarean birth to reduce the risk of passing it on to the baby. If your partner has herpes, use condoms or avoid sex when you’re pregnant (NHS Choices, 2018).

Zika virus

Zika virus is carried by mosquitoes. Zika began in South and Central America and the Caribbean, before spreading to Southeast Asia and the Pacific region. Zika virus causes birth defects if a pregnant woman catches it (NHS Choices, 2018).

Specifically, it can cause the baby to have an abnormally small head (microcephaly).

If you’re planning to travel to any regions affected by the Zika virus, get travel advice. It’s recommended that pregnant women postpone non-essential travel to high-risk areas.

This page was last reviewed in February 2018

Further information

Our support line offers practical and emotional support with feeding your baby and general enquiries for parents, members and volunteers: 0300 330 0700.

We also offer antenatal courses which are a great way to find out more about birth, labour and life with a new baby.

More information on infections, including sexually transmitted infections, whooping cough and blood poisoning can be found on NHS Choices. There is also an A-Z of common health problems which lists several common infections, and you can search for your nearest sexual health clinic.

Mor G, Cardenas I. (2010) The immune system in pregnancy: a unique complexity. American Journal of Reproductive Immunology. 63(6):425-433. Available from:  [Accessed: 1st February 2018]

NICE (National Institute for Health and Care Excellence). (2017) Antenatal care for uncomplicated pregnancies. Clinical guidelines [CG62]. Available from: [Accessed: 1st February 2018]

NHS Choices. (2016a) The flu jab in pregnancy. Available from: [Accessed: 1st February 2018]

NHS Choices. (2016b) Whooping cough. Available from: [Accessed: 1st February 2018]

NHS Choices. (2018) Infections in pregnancy that may affect your baby. Available from: [Accessed: 1st February 2018]

RCOG (Royal College of Obstetricians and Gynaecologists). (2012) Bacterial sepsis in pregnancy. Green-top Guideline No. 64a. Available from: [Accessed: 1st February 2018]

Schneeberger C, Geerlings SE, Middleton P, Crowther CA. (2015) Interventions for preventing recurrent urinary tract infection during pregnancy. Cochrane Database Systematic Review. (7):CD009279. Available from:  [Accessed: 1st February 2018]

Vazquez JC, Abalos E. (2011) Treatment for symptomatic urinary tract infections during pregnancy. Cochrane Database Systematic Review. (1):CD002256  Available from: [Accessed: 1st February 2018]

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