BNF · NICE · RCOG GTGs

Antibiotic Pocket Guide

OB-GYN infections at a glance

GBS prophylaxis (intrapartum)

  • Benzylpenicillin 3 g IV loading → 1.5 g IV every 4 h until delivery.
  • Penicillin allergy (non-severe): cefuroxime 1.5 g IV loading → 750 mg q8h.
  • Severe allergy: vancomycin 1 g IV q12h (measure levels).

PID (outpatient)

  • Ceftriaxone 1 g IM single dose + doxycycline 100 mg PO BD for 14 d + metronidazole 400 mg PO BD for 14 d.
  • Pregnancy: replace doxycycline with azithromycin/erythromycin.

Chorioamnionitis

  • IV amoxicillin 2 g q6h + gentamicin 5 mg/kg once daily + metronidazole 500 mg IV q8h.
  • Continue until 24 h afebrile.

Endometritis (postpartum)

  • Clindamycin 900 mg IV q8h + gentamicin 5 mg/kg OD until 24 h afebrile.
  • Add ampicillin if enterococcal cover needed.

UTI in pregnancy

  • First line: nitrofurantoin 100 mg BD 7 d (AVOID after 36/40 & at term).
  • Alternative: cefalexin 500 mg TDS 7 d, or amoxicillin 500 mg TDS if sensitive.
  • Avoid trimethoprim in T1 (folate antagonist).

Mastitis

  • Flucloxacillin 500 mg QDS 10–14 d. Continue breastfeeding.
  • Allergy: erythromycin 250–500 mg QDS.

Common mistakes

  • Giving nitrofurantoin at term → neonatal haemolysis.
  • Trimethoprim in T1 → NTDs; safe in T2/T3 if needed.
  • Doxycycline in pregnancy → dental staining, growth inhibition.
  • Metronidazole 'avoided' myth — safe throughout pregnancy at standard doses.

For educational use only

Not medical advice. Verify dosing against the BNF and your local trust guidelines before prescribing.