What neonatal complication is most likely to be reduced by administering IV antibiotics to a 32-year-old gravida 3 (G3) woman at 33 weeks gestation with premature rupture of membranes (PROM) for 4 hours, who is vitally stable with no uterine contractions?

Neonatal Sepsis is the Primary Complication Reduced by IV Antibiotics in PPROM

The correct answer is A. Sepsis. IV antibiotics administered to women with preterm premature rupture of membranes (PPROM) directly reduce neonatal sepsis through prevention of vertical bacterial transmission from mother to neonate. 1, 2, 3

Primary Mechanism of Benefit

• Antibiotics reduce vertical transmission of bacteria (particularly Group B Streptococcus) from mother to neonate, providing 86-89% effectiveness in preventing early-onset neonatal sepsis. 3

• The reduction in neonatal infection is statistically significant, with a relative risk of 0.67-0.68 (95% CI 0.52-0.87), meaning antibiotics reduce neonatal infection by approximately one-third. 4, 5

• Antibiotics administered ≥4 hours before delivery are highly effective at preventing vertical GBS transmission and early-onset GBS disease. 1

Why the Other Options Are Incorrect

Retinopathy of Prematurity (Option B)

• Antibiotics have no effect on retinopathy of prematurity, which is primarily related to oxygen exposure and prematurity itself, not infection. 3

Intracranial Hemorrhage (Option C)

• While some studies suggest antibiotics may reduce abnormal cerebral ultrasound findings (RR 0.82,95% CI 0.68-0.99), this finding is less consistently demonstrated across guidelines compared to sepsis reduction. 4, 5
• The mechanism is indirect—likely through prolonging latency and reducing inflammation—rather than a direct preventive effect. 3

Respiratory Distress Syndrome (Option D)

• Antibiotics have no significant direct effect on RDS prevention. 3
• RDS prevention requires antenatal corticosteroids, not antibiotics. 3, 6
• Any observed reduction in RDS with antibiotic use is secondary to prolonged latency allowing more time for corticosteroid administration and fetal lung maturation, not a direct antibiotic effect. 1

Clinical Context for This Case

• At 33 weeks gestation with PPROM, the patient should receive a 7-day antibiotic 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 days. 1, 2, 7

• This regimen carries a GRADE 1B recommendation (strong recommendation, moderate quality evidence) for PPROM ≥24 weeks gestation. 1, 2

• Avoid amoxicillin-clavulanic acid (Augmentin), which increases necrotizing enterocolitis risk in neonates (RR 4.60,95% CI 1.98-10.72). 4, 5

Additional Benefits Beyond Sepsis Reduction

• Antibiotics also reduce maternal chorioamnionitis (RR 0.57,95% CI 0.37-0.86). 5

• They prolong latency, reducing delivery within 48 hours (RR 0.71) and within 7 days (RR 0.80). 4, 5

• Secondary neonatal benefits include reduced surfactant use (RR 0.83) and oxygen therapy requirements (RR 0.88), but these are indirect effects of infection prevention and prolonged latency, not primary mechanisms. 4, 5