1. women at increased risk should be offered antibiotics immediately at the onset of labour or rupture of membranes (i.e. women known to carry GBS where no other clinical risk factors are present, and women not known to carry GBS who have another risk factor).
2. women at particularly high risk should be strongly advised to accept intravenous antibiotics immediately at the onset of labour or rupture of membranes until delivery (i.e. women who carry GBS who have one or more clinical risk factors, women who have previously had a baby infected with GBS, regardless of other risk factors and women who are not known to carry GBS who have multiple risk factors).
3. for women in labour, the recommended doses of penicillin G are 3 g (or 5 MU) intravenously initially and then 1.5 g (or 2.5 MU) at 4-hourly intervals until delivery. For women who are allergic to penicillin, the recommended doses of clindamycin are 900 mg intravenously every 8 hours until delivery.
4. intravenous antibiotics should be given for at least 4 hours prior to delivery where possible.
5. babies born in situations where there is increased risk and the mother has received at least 4 hours of intravenous antibiotics should be assessed carefully by a paediatrician and, if completely healthy, intravenous antibiotics should not be given to them (see chart below).
6. babies born in a higher risk situation where the mother has not received at least 4 hours of intravenous antibiotics should be investigated and initially commenced on antibiotics until it is fully established that the baby is not infected.

Recognised Risk Factors for GBS infection in Newborn Babies:
The 7 recognised risk factors for a newborn baby developing GBS infection are:

• Clinical risk factors: each one increases the risk at least 3 times:
  • where labour is preterm (prior to 37 completed weeks of pregnancy);
  • where there is preterm rupture of membranes (i.e. prior to 37 completed weeks of pregnancy) with or without other signs of labour;
  • where there is prolonged rupture of membranes (more than 18 to 24 hours before delivery) with or without other signs of labour; and
  • where the pregnant woman has a raised temperature (37.8°C or higher) during labour*.

• Increase the risk of the baby developing GBS infection at least 4 times:
  • where the pregnant woman is found to carry GBS during the pregnancy; and
  • where the pregnant woman has GBS bacteria in her urine at any time during the pregnancy (which should, of course, be treated at the time of diagnosis).

• Increases the risk of the baby developing GBS infection about 10 fold:
  • where the pregnant woman has previously had a baby who developed GBS infection.

There is no evidence to support the antenatal treatment of asymptomatic women colonised with the group B streptococcus (GBS).

Current recommendations are that all women with a history of having delivered an infant with GBS infection or of preterm rupture of the membranes, and all women found incidentally to have GBS in the urine or vagina during the current pregnancy should be offered intrapartum chemoprophylaxis.

See also

Royal College of Obstetricians and Gynaecologists,
Effective Procedures in Maternity Care
Section 5.4 Group B streptococcal infection. (See points 31-32)

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