Factors Associated With Lower Risk for Early-Onset Sepsis in Premature Infants

Newborn infant inside incubator
Newborn infant inside incubator
Identification of premature infants at low risk of early onset sepsis may help guide decisions for initiating and/or discontinuing empirical antibiotic treatments in the first days of life.

Premature infants who were delivered by cesarean section, had membrane rupture at delivery, and in whom there was no maternal clinical chorioamnionitis were at a low risk for early-onset sepsis, according to the results of a study published in Pediatrics.

To determine the impact of delivery characteristics on the risk for early-onset sepsis, outcomes for 15,433 infants born between 22 and 28 weeks of gestation were evaluated. The rates of early-onset sepsis, mortality, and morbidity were compared between infants who were hypothesized to be low risk (n=5759, 37%) and those who were not low risk (n=9674, 63%). Low-risk infants were considered to have all of the following delivery characteristics: cesarean delivery, membrane rupture at delivery, and no maternal clinical chorioamnionitis.  

Among the 5640 low-risk infants and 8422 comparison infants who survived more than 12 hours, 0.5% and 2.5% had early-onset sepsis (adjusted relative risk [RR] 0.24; 95% CI, 0.16-0.36).

Infants classified as low risk had a lower rate of mortality within the first 12 hours after birth compared with other infants (2.1% vs 12.9%). Moreover, the low-risk group had a lower rate of the composite outcome of mortality within 12 hours and early-onset sepsis (2.6% vs 15.1%; adjusted RR 0.36; 95% CI, 0.30-0.43).

Fewer infants in the low-risk group who survived more than 12 hours received antibiotics compared with the non-low-risk group (34.1% vs 47.4%, P <.001).

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The study authors noted that “delivery characteristics of infants born at 22 to 28 weeks [gestational age] were useful in identifying those with significantly lower risk of [early-onset sepsis]….Recognition of differential [early-onset sepsis] risk may help guide early empirical antibiotic use among approximately one-third of extremely preterm infants.”


Puopolo KM, Mukhopadhyay S, Hansen NI, et al; NICHD Neonatal Research Network. Identification of extremely premature infants at low risk for early-onset sepsis [published online October 5, 2017]. Pediatrics. doi: 10.1542/peds.2017-0925