The predictive value of maternal inflammation markers for neonatal early-onset sepsis

Maternal infection is a known risk factor for neonatal early-onset sepsis (EOS). However, the relationship between maternal inflammatory makers near delivery and neonatal EOS remains unclear. This study aimed to evaluate these associations and explore whether maternal blood parameters could contribute to EOS risk assessment strategies.

In this retrospective multicenter study in Hong Kong, we included mother‑neonate pairs where the mother underwent a complete blood count (CBC) or C-reactive protein (CRP) test between 48 h before and 72 h after delivery from January 1, 2006 to December 31, 2017. We assessed associations between maternal white blood cell count (WCC), absolute neutrophil count (ANC), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and CRP with subsequent neonatal EOS.

Among 380,455 mother‑neonate dyads, 460 neonates developed EOS. Markedly elevated maternal WCC, ANC, NLR, and PLR within 24 h before delivery were significantly associated with neonatal EOS, particularly in neonates born at ≥30 weeks' gestation. Within 12 h before delivery, the estimated likelihood ratios (LRs) for WCC > 30 × 10^9/L, ANC > 30 × 10^9/L, NLR > 50, and PLR > 800 were 23.8, 73.1, 45.7, and 45.6, respectively, in neonates born at 30-36 weeks, and 36.4, 92.9, 20.9, and 17.5, respectively, in term neonates. LRs were even higher when markers were elevated earlier (within 24 to 12 h) before delivery, suggesting a temporal relationship between maternal inflammation and neonatal EOS risk.

Although maternal sepsis biomarkers are insufficient to diagnose neonatal EOS independently, their elevation is associated with increased risk and may support clinical risk stratification, particularly when occurring well before delivery.