What is Strep B? Is it a risk for pregnant women, can it be passed to babies, what to do if you’re worried

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Strep B is common in pregnant women and rarely causes any problems, according to the NHS

Strep A infections in children are rising in the UK, but what is Strep B and how does it differ from Strep A? Here’s what you need to know.

What is Strep B?

Group B Strep is a type of bacteria called streptococcal bacteria. It’s very common in both men and women and usually lives in the bottom (rectum) or vagina. It affects two to four women in 10.

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Strep B is normally harmless and most people will not realise they have it. It’s usually only a problem if it affects:

  • pregnant women – it could spread to the baby
  • young babies – it can make them very ill
  • elderly people or those who are already very ill – it can cause repeated or serious infections

Strep A, which refers to  Group A Streptococcus (GAS), is the name given to a type of bacteria sometimes found in the throat or on the skin. It usually causes mild illnesses such as a sore throat, but can cause other infections such as pneumonia and scarlet fever.

Is Strep B a risk for pregnant women?

Strep B is common in pregnant women and rarely causes any problems. It’s not routinely tested for, but may be found during tests carried out for another reason, such as a urine test or vaginal swab.

According to the NHS, if you have Strep B while you’re pregnant:

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  • your baby will usually be healthy
  • there’s a small risk it could spread to your baby during labour and make them ill - this happens in about 1 in 1,750 pregnancies
  • there’s an extremely small risk you could miscarry or lose your baby

If you had Strep B during pregnancy, there’s a small risk it could spread to your baby and make them very ill. If this happens, it’s usually soon after they’re born. Your baby may be monitored in hospital for up to 12 hours to check for any problems. They’ll be given antibiotics into a vein if they develop symptoms.

What should I look for after leaving hospital?

Occasionally, symptoms of Strep B infection can develop up to three months after birth. Call 999 or go to A&E if your baby gets any of these symptoms:

  • being floppy or unresponsive
  • grunting when breathing, or working hard to breathe when you look at their chest or stomach
  • very fast or slow breathing
  • an unusually high or low temperature
  • changes in their skin colour or blotchy skin
  • not feeding well or vomiting milk up
  • an unusually fast or slow heart rate

They may need treatment with antibiotics in hospital immediately. Most babies with a Strep B infection make a full recovery if treated, but some babies may develop serious problems like sepsis or meningitis.

What should I do if I’m worried about Strep B?

If you’re worried about Strep B, speak to your midwife or GP for advice. Talk to them about the risks to your baby and ask their advice about whether to get tested. Routine testing is not currently recommended and tests are rarely done on the NHS, but you can pay for one privately.

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If tests find group B strep, or you’ve had a baby that’s been affected by it before, you may need extra care and treatment.

You may be advised to:

  • speak to your midwife about your birth plan - they may recommend giving birth in hospital
  • contact your midwife as soon as you go into labour or your waters break
  • have antibiotics into a vein during labour - this can significantly reduce the risk of your baby getting ill
  • stay in hospital for at least 12 hours after giving birth so your baby can be monitored - this is not always necessary
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