What will antibiotics given to a mother with premature premature rupture of membranes (PPROM) for 4 hours without fever prevent in the neonate?

Antibiotics in PPROM Primarily Prevent Neonatal Sepsis

The correct answer is B - Sepsis. Antibiotics given to mothers with PPROM primarily prevent neonatal sepsis and other infectious complications in the neonate, not respiratory distress syndrome (RDS). 1, 2

Primary Mechanism: Prevention of Vertical Transmission

• Antibiotics reduce vertical transmission of bacteria from mother to neonate, preventing early-onset infectious complications including sepsis, pneumonia, and other neonatal infections. 1
• The Centers for Disease Control and Prevention emphasizes that antibiotics administered ≥4 hours before delivery are highly effective at preventing vertical Group B Streptococcus (GBS) transmission and early-onset GBS disease. 1
• Duration of antibiotic exposure directly correlates with reduction in neonatal colonization and infection risk. 1

Evidence for Sepsis Prevention

• The landmark NICHD trial demonstrated that antibiotics significantly reduced neonatal sepsis within 72 hours of birth (8.4% vs 15.6%; P=.01) in GBS-negative women with PPROM. 2
• Network meta-analysis showed erythromycin was effective for neonatal sepsis prevention (RR 0.74,95% CI 0.56-0.97). 3
• Antibiotics also reduced pneumonia rates (2.9% vs 7.0%; P=.04) in neonates. 2

Secondary Benefits on Other Neonatal Outcomes

• While antibiotics do reduce respiratory distress syndrome rates (40.5% vs 48.7%; P=.04), this is a secondary benefit mediated through prolonging latency, which allows more time for fetal lung maturation, not a direct preventive effect. 2, 1
• Antibiotics reduce necrotizing enterocolitis (2.3% vs 5.8%; P=.03), another infection-related complication. 2
• The primary mechanism for RDS reduction is longer latency allowing more fetal lung maturation, not direct prevention of RDS itself. 1

Recommended Antibiotic Regimen

• The Society for Maternal-Fetal Medicine recommends a 7-day course: IV ampicillin 2g every 6 hours plus erythromycin 250mg every 6 hours for 48 hours, followed by oral amoxicillin 250mg every 8 hours plus erythromycin 333mg every 8 hours for 5 additional days. 4, 1
• Avoid amoxicillin-clavulanic acid due to increased necrotizing enterocolitis risk. 4, 1
• Azithromycin can substitute for erythromycin when unavailable. 4

Clinical Context

• Antibiotics are strongly recommended for PPROM at ≥24 weeks gestation (GRADE 1B). 4
• The benefit is gestational-age dependent, with greater evidence for benefit at earlier gestational ages (<32 weeks). 5
• Antibiotics should be administered promptly, as the 4-hour duration mentioned in the question is sufficient for effective vertical transmission prevention. 1

Common Pitfall

The key distinction is that antibiotics directly prevent sepsis through antimicrobial action against vertical transmission, while any effect on RDS is indirect through latency prolongation. 1, 2 This is why the answer is sepsis (B), not RDS (A), even though both outcomes may improve with antibiotic use.