Effect of Intrapartum Antibiotic Exposure Time on Neonatal Sepsis: A Prospective Cohort Study

To examine the association between the duration of intrapartum antibiotic exposure (IAE) and the risk of culture-negative early-onset neonatal sepsis (EONS) and any late-onset neonatal sepsis (LONS) in the first week.

Preterm neonates (≤ 34 weeks) were enrolled into: Group A (no IAE; n = 282), Group B (IAE < 24 h; n = 204) and Group C (IAE ≥ 24 h; n = 84). The risk factors for EONS and LONS were noted and all neonates were followed up for culture-negative EONS (primary outcome). Secondary outcomes included culture-positive EONS, culture-negative and culture-positive LONS, and multidrug-resistant sepsis. A univariable followed by multivariable analysis of risk factors to predict culture-negative EONS and LONS was performed. The cut-off (Youden's index) of IAE associated with various outcomes was determined.

From group A through C, gestation and birth weight declined, and the proportion at risk of EONS increased. Culture-negative EONS incidence increased (9.57% vs. 12.74% vs. 36.90%, respectively, P_trends < 0.001), but its proportion among all EONS did not. Culture-positive LONS incidence declined (P_trends = 0.038). The proportion of culture-negative LONS among all LONS increased (P_trends = 0.024). Threshold values of 13.5 h and 4.5 h were associated with culture-negative EONS and culture-positive LONS in the first week, respectively. However, on adjusted analysis, IAE duration had no association with culture-negative EONS or LONS in the first week.

Duration of IAE is not independently associated with increased incidence of culture-negative EONS or any LONS.