Table 2.

Antibiotics used for intrapartum prophylaxis

Antibiotic	Intrapartum Indication	Placental Kinetics
Penicillin G27	Recommended for GBS prophylaxis	Cord blood levels > MIC for GBS <1 hour after administration
Ampicillin25,26,28,29	Recommended for GBS prophylaxis	Cord blood levels >MIC for GBS with 30 minutes of maternal administration Rapid (<1 hour after maternal dose) transfer into amniotic fluid Neonatal serum levels >MIC for GBS at 4 hours of age, if dose administered to mother >15 minutes prior to delivery
Cefazolin30-32	Recommended for GBS prophylaxis in case of mild maternal penicillin allergy (non-anaphylaxis)	Cord blood levels >MIC GBS within 20 minutes of maternal administration
Clindamycin33-35	Recommended for GBS prophylaxis in case of serious maternal penicillin allergy and GBS isolate sensitive to clindamycin	Cord blood levels ~50% of maternal levels and above MIC for GBS Poor transfer into amniotic fluid
Vancomycin40,41	Recommended for GBS prophylaxis in case of maternal serious penicillin allergy and GBS isolate resistant to erythromycin or clindamycin	Ex vivo placental studies predict cord blood levels < 10% of maternal levels. Study of 13 women demonstrated cord blood levels >MIC for GBS by 30 minutes after 60-90 minute maternal infusion completed
Ampicillin and gentamicin 34,42	Recommended when there is concern for intrapartum maternal intraamniotic infection	Gentamicin reaches lower levels in pregnant compared to non-pregnant women Cord blood levels ~40% of maternal levels Poor transfer into amniotic fluid
Cefazolin and gentamicin	Recommended when there is concern for intrapartum maternal intraamniotic infection, in case of mild maternal penicillin allergy
Vancomycin and gentamicin	Recommended when there is concern for intrapartum maternal intraamniotic infection, in case of serious maternal penicillin allergy

Ampicillin-sulbactam, piperacillin-tazobactam, cefoxitin, cefotetan and ertapenem are alternative regimens for empiric treatment of maternal intraamniotic infection.