Amniotic fluid interleukin-6 and the risk of early-onset sepsis among preterm infants

Background High concentrations of interleukin-6 (IL-6) have been demonstrat ed in amniotic fluid (AF) from women with intra-amniotic infection. Recent studies have reported that IL-6 levels in AF were related to an increase in neonatal morbidity; moreover, higher IL-6 plasma levels have been observed in neonates with sepsis. Methods. A cohort study was carried out at the National Institute of Perina tology in Mexico City. Inclusion criteria were the following: 1) preterm si ngleton pregnancy; 2)intact membranes at time of enrollment, and 3) written informed consent. Women with other complications of pregnancy were exclude d. Newborn sepsis during the first 72 h was defined as early-onset sepsis. Amniotic fluid was obtained at the moment of delivery. Amniotic fluid IL-G (AF IL-6) was determined by enzyme-linked immunoassays. Results. Ninety-three women met the criteria for enrollment in the study an d 31 (33%) of their newborns had early-onset neonatal sepsis. The mean AF I L-B in mothers of septic newborns was 5779 +/- 2804 pg/ml compared to 729 /- 382 pg/ml in mothers with noninfected neonates (p <0.001). AF IL-6 conce ntrations higher than 1250 pg/ml were significantly associated with early-o nset sepsis (OR 33.3; 95% CI 9.4-117.3) (p <0.001). Gestational age under 3 2 weeks was also associated with neonatal sepsis (OR 2.56; 950/c CT 1.2-9) (p = 0.002). Women whose infants developed neonatal sepsis had a higher fre quency of clinical chorioamnionitis (p = 0.02). Conclusions. IL-6 determination in AF may be a useful indicator to identify neonates with higher risk of in utero bacterial infection. (C) 1999 IMSS. Published by Elsevier Science Inc.