Intrapartum prophylaxis and the newborn

OSCE stationVivaEarly-onset sepsis

A viva on GBS screening, what counts as adequate intrapartum prophylaxis, and what that means for the newborn.

Questions

1. When does ACOG, as cited by the AAP, recommend antenatal GBS testing, and how?

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   • Universal antenatal testing with vaginal-rectal cultures at 36 0/7 to 37 6/7 weeks.

2. What agents count as adequate intrapartum prophylaxis, and what timing makes it adequate?

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   • CPS: at least one dose, given at least 4 hours before birth, of IV penicillin G or ampicillin, or IV cefazolin if the mother is allergic to penicillin but at low risk of anaphylaxis.
   • AAP: penicillin G is preferred for its narrower spectrum; ampicillin is acceptable.

3. A mother with a high-risk penicillin allergy received clindamycin. How should this be regarded when managing her baby, and why?

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   • As inadequate prophylaxis when managing the neonate, because the efficacy of clindamycin and vancomycin regimens has not been confirmed in clinical trials (CPS).
   • AAP: clindamycin does not reach significant amniotic fluid concentrations until several doses have been given, and one study found a clinical effectiveness of only 22%.

4. When is intrapartum prophylaxis not recommended regardless of GBS status?

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   • When a caesarean section is performed before the onset of labour with intact membranes.

Based on: American Academy of Pediatrics, Management of infants at risk for group B streptococcal disease (Pediatrics, 2019); Canadian Paediatric Society statement (2017).