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