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GBS and Pregnancy

“Every pregnant woman should read this leaflet – it could save her baby’s life.”
says Dr Chris Steele

Using the information in this leaflet can dramatically reduce the chances of your baby developing life threatening group B Streptococcal (GBS) infection.

  • GBS is the most common cause of life-threatening infection in newborn babies in the UK
  • GBS infections in newborn babies can usually be prevented – by identifying pregnant women whose babies are at higher risk and managing their pregnancy and delivery appropriately

What is GBS?
Group B Streptococcus (GBS) is a very common bacterium. It occurs naturally in many people, from babies to the elderly, and typically causes no harm or symptoms. Carrying GBS (also called GBS colonisation or GBS carriage) is entirely normal – up to one in every three people carries GBS in the gut (bowel), and in women it is often also found in the vagina. Carrying GBS can be intermittent – it can come and go – but simply carrying GBS does not require treatment.

What is GBS infection?
GBS carriage is harmless, but it can cause infection. GBS infection (when the bacterium starts to cause harm) occurs most often in newborn babies before, during or shortly after birth – thankfully this happens relatively rarely (approximately one in every 1,000 babies). However, this still means that UK wide, 700 babies a year develop GBS infection. Up to 10% of babies infected with GBS die and survivors can be left with serious mental or physical disabilities.

GBS infection affects approximately 700 babies a year – it can usually be prevented

Babies who develop GBS infections can be exposed to GBS in the womb, during labour, during birth and following birth.

Many babies are exposed to GBS, but only those susceptible to the bacterium will become infected. It is not yet known what makes one baby susceptible and another one not.

Very rarely, GBS can infect the waters surrounding the baby or the womb itself before birth (giving antibiotics routinely during pregnancy does not reliably prevent this). Occasionally, the urinary tract of the mother can be infected (before or after birth); this does require antibiotic treatment at the time of diagnosis.

What do I need to know about GBS?
GBS infection in the newborn can usually be prevented by identifying women carrying GBS at delivery, and giving them intravenous antibiotics from the beginning of labour or waters breaking until delivery.

GBS infection in babies can be prevented

If GBS is found in a woman’s urine at any time during her pregnancy then this is an infection and should be treated promptly with oral antibiotics. However, giving antibiotics to women who are simply carrying GBS is not effective at preventing GBS infection.

Caesarean section does not eliminate the risk of GBS infection in newborn babies and, has risks for mother and baby. Caesareans are not recommended to prevent GBS infection in babies.

GBS can be carried on the skin, so everyone, whether they carry GBS or not, should wash and dry their hands properly before handling a baby during its first three months of life.

How do I know if I am carrying GBS?
There are two tests available to mothers – one is available on the NHS, usually called an HVS (High Vaginal Swab) or LVS (Low Vaginal Swab) test. The other – called the ECM (Enriched Culture Medium) test is available privately and from a handful of NHS hospitals. Currently, neither the HVS nor LVS test is routinely used to detect GBS carriage in the NHS. Moreover, these tests only detect carriage in up to 50% of women carrying the germ. The ECM test is considered the “Gold Standard” and is the best GBS screening available.

Colonisation of the vagina with GBS produces no symptoms and can be intermittent. To predict with the best accuracy the chances of carrying GBS at delivery, the best time to test for it is between 35–37 weeks of pregnancy.

Carrying GBS in the vagina does not automatically mean a baby will develop GBS infection.

What are the tests?
The HVS/LVS test involves taking a swab from the vagina. A positive result with the HVS test is very reliable – however it can give a falsely negative result for up to 50% of women carrying GBS when the test is done – leaving them under the false impression that they are not carrying GBS, and their baby is at no risk. An LVS is slightly more likely to detect colonisation than a HVS, but it is still gives many false negatives.

A much more sensitive test for GBS colonisation is available privately and from a handful of NHS hospitals – called the ECM (or Enriched Culture Medium) test, and currently costs around £32 for a postal service. The test involves taking a swab from the vagina and rectum at 35–37 weeks of pregnancy, and posting them back to the laboratory. Earlier testing is not good at predicting GBS colonisation at delivery, and later testing increases the chance that the baby will be born before the result is available. It is important that you discuss this test with your health professional, and ensure they receive a copy of the test results. If done within 5 weeks of delivery, this test is very sensitive: if you have a positive result for GBS, there is an 87% chance that you will carry GBS at delivery. Similarly, if you have a negative result this is 96% predictive that you will not be carrying GBS at delivery.

There is another test method called Polymerase Chain Reaction or PCR testing. Although this is believed to be a highly accurate and fast method of detecting GBS colonisation, it has not been validated in the UK and therefore GBSS is unable to recommend its use.

More information about testing is available from your health professional or Group B Strep Support (GBSS) (www.gbss.org.uk or 01444 416176).

Why test?
Testing is not essential, but it is the only way to know which babies are more likely to develop GBS infection, so that it can be prevented effectively. If a woman carries GBS during her current pregnancy, she should be offered intravenous antibiotics in labour to minimise the risk of GBS infection developing in her newborn baby. See Recommended preventative medicine later.

Regardless of which test you choose, or whether you decide not to test, you should be aware of the signs of GBS infection in your baby – these are described later in this leaflet.

Remember!
Women who have had a previous baby with GBS infection should ALWAYS be offered intravenous antibiotics from the onset of labour in all subsequent pregnancies. In these cases, testing is not necessary.

How do I know if my baby is at risk of GBS infection?
There are five situations where a baby is more likely to be exposed to GBS and run the risk of possible GBS infection. Each of the risk factors shown in the panel below increases the risk of GBS infection in a newborn baby.

Risk factors for GBS infection in newborn babies

  • Mothers who have previously had a baby infected with GBS – risk is increased 10 fold
  • Mothers who have been shown to carry GBS in this pregnancy or GBS has been found in the urine at any time during this pregnancy – risk is increased four fold

Each of the following clinical risk factors – risk of GBS infection is increased three fold

  • Labour starts or membranes rupture before 37 weeks of pregnancy is completed (i.e. preterm).
  • Where there is prolonged rupture of the membranes – more than 18 hours before delivery.
  • Where the mother has a raised temperature* during labour of 37.8°C or higher.

*If a woman has an epidural, a slightly raised temperature may be of less significance than in a woman with no epidural.

Simply carrying GBS previously without a positive test result this pregnancy does not mean a woman should be offered intravenous antibiotics in labour unless one or more other risk factors are also present.

How can GBS infection in babies be prevented?
Guidelines from the Royal College of Obstetricians and Gynaecologists (RCOG) have been produced. Key to these guidelines is the use of intravenous antibiotics, which has proven to be very effective in preventing GBS infections in newborn babies if given from the start of labour or waters breaking until delivery.

The use of any drug, including antibiotics, is not without risk however, so please discuss antibiotic options with your healthcare professional to make the best decision for you and your baby. Our medical advisory panel’s key recommendations for preventing GBS infection in newborn babies are:

Recommended preventative medicine:

Women at risk
Women at high risk should be strongly advised to have intravenous antibiotics immediately at onset of labour until delivery. At high risk means:

  • Women with GBS and another risk factor
  • Women who may/may not have GBS, but have multiple risk factors
  • Women who have had a previous baby infected with GBS
  • Women with a fever during labour

Women at increased risk should be offered intravenous antibiotics immediately at onset of labour through to delivery. At increased risk means:

  • Women who are known to carry GBS and do not have other risk factors
  • Women who do not know whether they carry GBS but have one other risk factor not mentioned above

Treatment approaches
Intravenous antibiotics against GBS infection in the baby should be given to the mother for at least four hours before delivery if possible (if only two hours is possible, this may be sufficient and should give considerable reassurance).

Intravenous antibiotics recommended for women in labour are Penicillin G: given as 3g (or 5MU) intravenously at first and then 1.5g (or 2.5MU) at 4-hourly intervals until delivery For women allergic to penicillin: Clindamycin 900 mg intravenously every 8 hours until delivery

Where infection of the membranes is diagnosed or suspected or where there is preterm prolonged rupture of membranes, broad spectrum intravenous antibiotics should be given which include adequate GBS cover.

If you are allergic to Penicillin or any other antibiotic, you MUST tell your health professionals

Care after birth
Babies born to mothers at increased/high risk who HAVE received antibiotics for 4 hours before delivery should be:

Carefully assessed by a paediatrician – if completely healthy no antibiotics for the baby are required. A period of monitoring (12–24 hours) may be appropriate for those at highest risk of infection.

Babies born to mothers at increased/high risk who HAVE NOT received antibiotics for 4 hours before delivery should be:

Examined thoroughly and investigated by a paediatrician as appropriate. Started on intravenous antibiotics until it is known that the baby is not infected, unless the baby is completely well as determined following a robust baby examination carried out by a trained individual.

How to recognise GBS infection in babies
GBS infection is usually of early onset in the first 6 days of life (hence called “early onset GBS infection”). Signs are apparent at or soon after birth in most (up to 60% of babies affected), and almost all (up to 90%) within the baby’s first 6 days. This usually appears as septicaemia with pneumonia. Late-onset GBS infection occurs after the baby’s first 6 days, it is uncommon after your baby reaches one month old and almost unknown after age 3 months. Late-onset GBS infection usually appears as meningitis with septicaemia.

The boxes below outline the signs and symptoms of GBS infection in the newborn and those of late-onset GBS infection.

Signs of GBS infection in newborn babies
Typical signs of early-onset GBS infection include:

  • Grunting
  • Poor feeding
  • Being abnormally drowsy (lethargic)
  • Being irritable
  • High/Low temperature
  • High/Low heart rate
  • High/Low breathing rate
  • Low blood pressure
  • Low blood sugar

Signs of late-onset GBS infection – including meningitis – warning signs may include one or more of the following:

  • High temperature, fever, possibly with cold hands and feet
  • Vomiting, refusing feeds or poor feeding
  • High pitched moaning, whimpering cry
  • Blank, staring or trance-like expression
  • Pale, blotchy skin
  • Baby may be floppy, may dislike being handled, be fretful
  • Difficult to wake or lethargic
  • The fontanelle (soft spot on babies’ heads) may be tense or bulging.
  • Turns away from bright light
  • Altered breathing pattern
  • Involuntary stiff body or jerking movements

Trust your instincts – it is your baby! If your baby shows signs consistent with GBS infection or meningitis, call your GP immediately. If your GP isn’t available, go straight to the nearest PAEDIATRIC Accident & Emergency Department. Early diagnosis and treatment are essential to combat late-onset GBS infection – delay can be fatal

GBS infection can be effectively treated
GBS infection can be successfully treated using aggressive intravenous antibiotic therapy and intensive care. Most babies will fully recover, especially if meningitis is not present. Sadly, despite the best medical care, approximately 10% of babies who develop GBS infection will die. Early-onset GBS infection accounts for over 80% of all GBS infections, and late-onset GBS infection up to 20%. Of babies who contract GBS meningitis, up to half may suffer long-term mental or physical problems, and for 1 in 8 of these babies the handicaps can be severe.

GBS infection is usually preventable
Up to 60% of cases of early-onset GBS infection can be prevented using the risk management table shown earlier in this leaflet, and offering intravenous antibiotics to pregnant women with any of these risk factors as soon as possible once labour has started.

Over 80% of early-onset GBS infection can be prevented when women are routinely screened for GBS carriage late in their pregnancy and when those found to carry GBS are also offered intravenous antibiotics as soon as possible once labour has started.

What should I do next?
Discuss GBS with your midwife and obstetrician and agree a pregnancy and birth plan that includes strategies to prevent GBS infection in your baby.

Remember!

  • Most GBS infection in newborn babies can be prevented
  • Pregnancy can normally be managed so that your baby can be protected against GBS infection
  • Good management of your pregnancy, using the recommendations listed in this leaflet reduces the risk of a baby developing GBS infection when born to a mother carrying GBS at delivery from one in 300 babies to less than one in 6,000

For more information about GBS, please speak with your health professional team Name/Contact details of your Midwife/health clinic:

Alternatively, information about GBS, including copies of this leaflet, can be found on the Group B Strep Support (GBSS) website www.gbss.org.uk and easily downloaded, or contact:

Group B Strep Support, PO Box 203,
Haywards Heath, West Sussex RH16 1GF
E-mail: info@gbss.org.uk
Tel: 01444 416176
Fax: 0870 803 0024 (calls charged at national rates)
www.gbss.org.uk
Registered charity number: 1112065
Registered company number: 5587535

All of our leaflets can be downloaded from our website

Group B Strep Support is a national charity providing accurate and up-todate information on GBS for families and health professionals.

GBSS wants to see sensitive GBS testing available to all pregnant women on the NHS. Until this time, GBSS supports the Royal College of Obstetricians and Gynaecologists’ national guidelines to identify women and babies at risk of GBS infection through identification of risk factors.

GBSS has no financial links with any laboratories.

Key medical references

  • Law MR, Palomaki G, Alfirevic Z et al. The prevention of neonatal group B streptococcal disease. J Med Screening 2005;12:60–8.
  • Heath PT, Balfour G, Weisneer AM et al. Group B streptococcal disease in UK and Irish infants younger than 90 days. Lancet 2004;363:292–4.
  • RCOG Clinical Green Top Guidelines. Prevention of early onset neonatal group B streptococcal disease [36] November 2003. www.rcog.org.uk/resources/public/pdf/groupb_strep_no36.pdf
  • Centers for Disease Control & Prevention. Prevention of perinatal group B streptococcal disase: Revised guidelines from CDC. MMWR August 2002;51(RR11):1–22. www.cdc.gov/mmwr/preview/mmwrhtml/rr5111a1.htm
  • Oddie 2, Embleton N. Risk factors for early onset neonatal group B streptococcal sepsis: case-control study. BMJ 2002; 325: 308.
  • Benitz WE, Gould JB, Druzin ML. Risk factors for early-onset group B streptococcal sepsis: estimation of odds ratios by critical literature review. Pediatrics. 1999 Jun;103(6):e77
  • Yancey MK, Schuchat A, Brown LK et al. The accuracy of late antenatal screening cultures in predicting genital GBs colonization at delivery. Obstet Gynecol 1996;88:811–5.