GBS Positive in Pregnancy: What Does It Mean for Labour?

Being GBS positive in pregnancy means group B streptococcus bacteria were found in a urine sample or a vaginal or rectal swab. GBS is a common bacterium that usually lives harmlessly in the gut and vagina, and most people who carry it have no symptoms. The main reason it matters is that it can occasionally pass to the baby around birth, so the care team usually offers antibiotics during labour.

This guide explains what UK and US sources say about GBS carriage, labour care and newborn warning signs. It is general education. Your own maternity team will advise on your situation, including your birth plan and any allergies.

For you during pregnancy, the NHS advises contacting your midwife or maternity unit as soon as labour starts or your waters break if you carry GBS, so antibiotics can be started in time. RCOG says antibiotics should start as soon as possible after labour begins or the waters break.

Also call your midwife or maternity unit straight away if your baby is moving less than usual, the pattern changes, or you cannot feel movement. The NHS says not to wait until the next day.

For your baby after birth, the NHS advises calling emergency services (999 in the UK) or going to an emergency department if a baby shows signs of GBS infection. Mention that you carry GBS.

• Being floppy or not responding normally, or being unusually sleepy.
• Grunting when breathing, noisy breathing or working hard to breathe.
• Very fast or very slow breathing, or an unusually fast or slow heart rate.
• An unusually high or low temperature.
• Changes in skin colour or blotchy skin.
• Not feeding well or vomiting milk up.

Very common. RCOG estimates that 2 to 4 in 10 women in the UK carry GBS. It is not a sexually transmitted infection. The CDC describes the bacteria as coming and going naturally in people's bodies.

Because carriage can change over time, a result from earlier in pregnancy, or from a previous pregnancy, may not show whether GBS is present at the time of birth. The NHS describes the risk of GBS spreading to the baby during labour as small, and most babies of people who carry GBS are healthy.

Practice differs between countries. In the UK, the NHS does not routinely test everyone for GBS. It is often found by chance in a urine test or swab done for another reason. RCOG describes an enriched culture medium (ECM) swab that may be offered at 35 to 37 weeks in some situations, such as when GBS was found in a previous pregnancy.

In the United States, the CDC says all pregnant women should be screened for GBS. MedlinePlus describes a swab from the vagina and rectum taken late in pregnancy. Ask your own team when and how testing is done where you live.

RCOG, the CDC and MedlinePlus all describe antibiotics given into a vein (by drip) during labour. These sources explain that antibiotics taken earlier in pregnancy do not reliably help, because the bacteria can come back before birth. RCOG says the drip is usually repeated at intervals until the baby is born. Doses and choice of medicine are decided by the team.

MedlinePlus adds that antibiotics in labour may also be offered to people with certain risk factors even without a positive test, such as labour or waters breaking before 37 weeks, waters broken for 18 hours or more without delivery, a fever during labour, a previous baby with GBS infection, or a past urine infection caused by GBS.

RCOG and MedlinePlus explain that antibiotics specifically for GBS are not usually needed for a planned caesarean if labour has not started and the waters have not broken, although antibiotics are routinely offered at caesarean for other reasons. RCOG says that if your waters break after 37 weeks and you carry GBS, you will be offered induction of labour straight away, with antibiotics.

The NHS notes that a hospital birth may be recommended and that some babies are monitored for a period after birth. Ask your team how this applies to your birth plan.

Penicillin-type antibiotics are the usual choice for GBS in labour, according to RCOG and the CDC. Both say that people who are allergic can be offered a suitable alternative antibiotic.

Tell your midwife or doctor early about any penicillin allergy and what happened when you reacted, for example a rash or breathing problems. This helps the team plan which antibiotic to use before labour starts. Do not decide on or take antibiotics yourself.

RCOG explains that early-onset GBS infection usually shows within 12 to 24 hours of birth. Late-onset infection can happen up to 3 months of age, and antibiotics in labour do not prevent it. That is why it helps to know the warning signs listed above for the first few months, not just the first day.

RCOG states that breastfeeding is safe and has not been shown to increase the risk of GBS infection. If anything about your baby worries you, contact a healthcare professional urgently and say that you carry GBS.

These questions can help you understand your own plan.

• Where was GBS found: urine, vaginal swab or rectal swab?
• Will I be offered antibiotics in labour, and how soon after labour starts?
• What should I do if my waters break before labour starts?
• I have a penicillin allergy. Which alternative will be used, and should I tell anyone else before labour?
• Does being GBS positive change where you recommend I give birth?
• How will my baby be monitored after birth, and for how long?
• Will GBS affect care in a future pregnancy?

On SameCase, patients and verified doctors share de-identified cases. Reading how others described being GBS positive, their labour plans and the questions they asked may help you prepare for your own appointments. Other people's experiences cannot tell you what will happen in your pregnancy. Your maternity team remains the right place for decisions about your care.