Infections during pregnancy

If you’re wondering why you’re susceptible to every cold going while you’re pregnant, it’s because your immune system is moderated, possibly to prevent your body rejecting your baby (Mor and Cardenas, 2010).

Infections to be aware of when you’re pregnant include:

• urinary tract infections (UTIs)
• COVID-19
• monkeypox
• chickenpox
• German measles/rubella
• flu
• whooping cough
• cytomegalovirus (CMV)
• group B streptococcus (GBS)
• sexually transmitted infections (STIs)
• zika virus (if you are planning to travel).

(NHS, 2021a)

COVID-19

COVID-19 symptoms are similar to that of flu and the virus spreads in a similar manner, through respiratory droplets and contaminated surfaces (NHS, 2022a).

The main symptoms include a high temperature, a persistent cough and a loss of taste and smell. While many people will have no symptoms at all, some evidence suggests that infection during pregnancy carries an increased risk of serious illness, particularly in the third trimester. It is therefore highly recommended that pregnant women are up to date with their COVID-19 vaccinations (NHS, 2022a). 

Monkeypox

Monkeypox is caused by a zoonotic virus and is transmitted through close contact with an infected person or animal. Infection happens when you encounter an infected person – through their skin lesions, their bodily fluids or their respiratory droplets as well as recently contaminated objects.

Infection usually results in a rash, a fever and swollen lymph nodes. Research into the effects of monkeypox on pregnant or breastfeeding women and on infants and young children remains low but we do know that it can pass from mother to foetus. You should contact your GP if you believe you, or your child, have been in close contact with someone who has monkeypox.

Urinary tract infections

Urinary tract infections (UTIs) are caused by bacteria entering the urinary tract and are very common during pregnancy (NHS, 2022b). Fortunately UTIs are usually easy to treat. The NHS suggests contacting your pharmacist first for suggestions, including guidance on whether you need to see a GP (NHS, 2022b).

Rarely, or if untreated, a UTI can lead to more serious complications for you and your baby (Vazquez and Abalos, 2011; Schneeberger et al, 2015).

UTIs are more common when you’re pregnant  because of changes in the urinary tract due to pregnancy hormones, and because it’s harder during pregnancy to completely empty your bladder (as you’ll know when you’re in the loo at 3am) (Vazquez and Abalos, 2011; Habak and Griggs, 2021). 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).

Suggestions on how to avoid UTIs include: 

• after you use the toilet, wipe yourself from front to back 
• make sure your genital area stays clean and dry 
• have plenty of drinks (especially water) in the day to make sure you have a wee regularly 
• use water to wash the skin around your vagina before and after you have sex 
• have a wee as soon as you can after you have sex. 

(NHS, 2022b) 

Chickenpox

Chickenpox during pregnancy can be dangerous for both you and your baby. So if you get it, call your GP straight away (NHS, 2021a).

Nine out of ten people are immune to chickenpox due to having it as a child and in some countries a vaccine is offered to protect against the virus that causes it (Shaw and Gershon, 2018). If you think you may be at risk because you have not had chickenpox or the vaccine before and you have come into contact with someone who has it, contact your midwife or GP for a blood test that can check your immunity (NHS, 2021a).

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, 2021a).

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, 2019).

Flu

Flu can cause serious complications especially during the later stages of pregnancy. It can lead to chest infections for the pregnant woman and could cause the baby to be born early, have a low birth weight or be stillborn. So whatever stage of pregnancy you’re at, book in for the flu jab to protect yourself and some of that protection also passes to the unborn baby (NHS, 2019a). 

The flu vaccine is safe and it is a good idea to get it before flu starts circulating in the winter months (NHS, 2019a). The flu virus changes every year so even if you had the flu jab previously, there are benefits to having it again (NHS, 2019a). 

If you are pregnant and you think you are developing the flu, contact your GP as medication may help and is most effective if taken soon after symptoms appear (NHS, 2019a). 

Whooping cough

Whooping cough, also called pertussis, is a contagious bacterial infection of the lungs and airways that causes long bouts of coughing and choking. Cases have risen sharply over recent years and it can cause young babies to be very unwell and most will need to be admitted to hospital because of the illness (NHS, 2019a,b). 

To protect babies before they are old enough for their first vaccine at eight weeks, it is recommended that pregnant women are vaccinated between 16 and 32 weeks of pregnancy (NHS, 2019b).

CMV 

Cytomegalovirus (CMV) is a common virus that is normally harmless in healthy adults and may only cause flu-like symptoms at the first infection. Most adults have had it as a child and are unlikely to develop or spread an infection. However children at first infection, and people with a weakened immune system, are at risk of passing on active CMV.

If a pregnant person is infected, it may pass to the baby, which can lead to hearing loss, blindness, learning difficulties or epilepsy (NHS, 2020; NHS, 2021a). 

The main way a pregnant woman catches CMV is from interacting with young children. So if you have young children or work with young children, you may wish to avoid interacting with those who are unwell (NHS, 2020). 

At the moment, there’s no vaccine against CMV. Ways to protect yourself include: 

• Washing hands using soap and water after changing nappies, wiping noses, feeding, etc. 
• Washing toys or other things that get children’s saliva or urine on them. 
• Not sharing cups, cutlery etc. with your young children. 
• Avoiding kissing babies, toddlers and small children directly on the mouth. Kiss them on the forehead or cheek instead. 

(Stowell et al, 2013; NHS, 2020; NHS, 2021a) 

Group B strep 

Group B strep rarely causes harm or symptoms in pregnancy but in a few cases (1 in 1750) it can pass to the baby just before or during labour, which can lead to more serious illness (NHS, 2021a,b). It is not routinely tested for in the UK but may be spotted in a test carried out for another reason. 

If a group B strep infection is discovered, then intravenous antibiotics will be offered during labour and your baby may be monitored in hospital after birth (NHS, 2021a). Most babies with a group B strep infection make a full recovery but it is important to recognise the signs of a baby being unwell and to seek medical advice quickly if you are concerned (NHS, 2021b).  

You can read more about when to seek medical advice in our article: When to call a doctor about your baby. 

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, 2021a).

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, 2021a).

Herpes in pregnancy

Genital herpes is a sexually transmitted infection that is passed on through vaginal, anal and oral sex. It can be dangerous for a newborn baby (NHS, 2021a).

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, 2021a).

To reduce the chance of contracting all sexually transmitted diseases, have honest conversations with your sexual partner, use a condom or avoid sex. 

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 can cause birth defects if a pregnant woman catches it (NHS, 2021a). 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 and avoid pregnancy for three months after visiting these areas (NHS, 2021a). 

Sepsis (maternal sepsis) 

Maternal sepsis is a rare but serious illness, which can happen as a complication of a severe infection in pregnancy or after birth. Read about the symptoms to watch out for here.

Sepsis is the third leading cause of deaths in women giving birth in the UK, so it’s important to be aware of the symptoms and to seek medical aid quickly if you are concerned (MBRRACE-UK, 2021; NHS Inform, 2022). 

Not all sepsis is caused by the individual but you can reduce the chance of infecting yourself by focusing on good hygiene practices. After birth, washing your hands before and after changing a sanitary pad or touching the perineum will help prevent infections occurring. You can also avoid close contact with anyone who is ill (RCOG, 2012).  

This page was last reviewed in July 2022.

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 flu, whooping cough, COVID-19 and CMV can be found on the NHS website. 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.