[CG] Group B Streptococcal prophylaxis, obstetric guideline

All pregnant women should be provided with an appropriate information leaflet regarding GBS.

Universal bacteriological screening is not recommended. A maternal request for screening is not an indication, but should be discussed with healthcare professionals on an individual basis.

Antenatal treatment is not recommended for GBS cultured from a vaginal or rectal swab. Women with GBS urinary tract infection (> 10⁵  cfu/ml) during pregnancy should receive appropriate treatment at the time of diagnosis, as well as intrapartum antibiotic prophylaxis.

1– Prophylaxis cases

The following groups of women should be offered IAP with an intravenous antibiotic which is effective against GBS. This will be benzylpenicillin or, for penicillin sensitive women, teicoplanin.

• Women in whom colonisation with GBS has been identified in current or previous pregnancy
• Women with GBS bacteriuria in current or previous pregnancy
• Women with previous baby affected by early- or late-onset neonatal GBS disease
• Women in confirmed preterm labour< 37⁺⁰ weeks gestation

Women with GBS detected in a previous pregnancy have a 50% risk of recurrent GBS carriage and should be offered routine IAP or the option of bacteriological testing in late pregnancy, followed by IAP if still positive.

If performed, bacteriological testing should be carried out at 35-37 weeks gestation or 3-5 weeks prior to the anticipated delivery date, i.e. 32-34 weeks gestation in multiple pregnancies. A single (Amies charcoal) swab should be taken from the lower vagina and anorectum. Healthcare professionals should indicate that the swab is being taken for GBS.

2– Potentially infected women who require antibiotics that also cover GBS

In women:

• Where chorioamnionitis is suspected
• Who have a pyrexia during labour (> 38°C) or a temperature of ≥ 37.5°C on 2 separate occasions at least 2 hours apart or maternal sepsis with a temperature < 36°C
• For whom the sepsis 6 bundle is triggered

Antibiotic therapy should be according to GGC guidelines but in addition, must include specific GBS prophylaxis as below.

Intrapartum prophylaxis

Effective prophylaxis

Prophylaxis is more effective if the first dose is given at least 4 hours prior to delivery and continued at the correct intervals. Antibiotics should be started as soon as possible after the onset of labour and continued until delivery. Prophylaxis is considered to have lapsed if a dose is more than 1 hour late. If prophylaxis with benzylpenicillin has lapsed a 3g loading dose is required rather than the routine 1.8g dose.

NB – As the primary goal of IAP is to prevent transmission of GBS to the neonate, it is vital to give effective prophylaxis even if the baby will receive antibiotics after delivery due to the presence of other risk factors for early onset sepsis.

Women who are receiving prophylactic antibiotics for GBS in labour who require a caesarean section will still require routine co-amoxiclav or clindamycin cover  (See antibiotic guideline).

Irrespective of gestation and the presence of risk factors for GBS transmission, IAP is not required if delivery is by planned caesarean section with intact membranes and the baby is clinically well.

Management of rupture of membranes to reduce the risk of GBS transmission

Women with rupture of membranes at term (≥ 37⁺⁰ weeks gestation) who are known GBS carriers should be offered immediate IAP and induction of labour as soon as reasonably possible.

Bacteriological testing for GBS carriage is not recommended for women with preterm prelabour rupture of membranes. IAP should be given once labour is confirmed or induced irrespective of GBS status. However, known GBS colonisation should be taken into consideration when making decisions about timing of delivery in women with preterm prelabour rupture of membranes. For those at more than 34+0 weeks of gestation it may be beneficial to expedite delivery if the woman is a known GBS carrier.

It  will  be  the  responsibility  of  the  labour ward  staff  to  communicate  to  the neonatologist  the following information:

• That risk factors for early onset neonatal GBS disease have been identified
• Whether prophylaxis has been started and, if so, how long prior to delivery
• Whether there is evidence of maternal sepsis

The requirement for prophylaxis should be recorded on the alert area in the maternal notes.
Remember if mother is septic ensure neonatologist informed.

Parents who decline intrapartum antibiotic prophylaxis or empirical treatment for their baby

We recommend GBS prophylaxis. Intrapartum prophylaxis may be declined despite this advice. Empirical therapy for well infants born to mothers with risk factors may also be declined.

If parents decline these interventions the medical staff should ensure that they are aware of the level of risk of early onset GBS disease and the life threatening nature of GBS sepsis. The infant should remain in hospital for at least 24 hours and observations of temperature, pulse and respiratory rate performed 3 hourly and recorded on a NEWS chart.

GBS prophylaxis is offered by maternity staff to the mother and this must be adequately explained. If the clinician is unable to answer any queries then a relevant professional should be asked to address any concerns. This should conclude with a decision as to whether prophylaxis is accepted or declined and this must be clearly documented.

When prophylaxis or empirical treatment is declined by informed parents, this should be documented. It is not appropriate to suggest or instigate child protection proceedings.

The baby should be monitored on a NEWS chart and treated with antibiotics if abnormal clinical signs or symptoms are identified (refer to EOS guideline for details). Parents may not decline therapy for their baby if signs or symptoms of infection are present.