Effect of chorioamnionitis on mortality, early onset neonatal sepsis and bronchopulmonary dysplasia in preterm neonates with birth weight of < 1,500 grams.

The aim of the study was to investigate the effects of chorioamnionitis on mortality and early onset neonatal sepsis (EONS) and bronchopulmonary dysplasia (BPD) in preterm neonates with birth weight < or = 1,500 g. The study included 395 preterm infants born at the Zagreb Clinical Hospital Center, from January 2001 to December 2005. All the placentas from preterm deliveries were sent for pathological examination. The patients were categorized into two groups: one including patients with chorioamnionitis at placental histology (47%) and the other control group without chorioamnionitis (53%). Neonates were distributed into 3 groups according to gestational age: the first group with 132 (33%) infants born at < or = 28 weeks of gestation, the second with 202 (52%) infant born from 29 to 32 weeks of gestation and the third with 61 (15%) infants born at > or = 33 weeks gestation. Chorioamnionitis was diagnosed significantly more often in the first gestational age group (91/132-69% of infants, chi2 = 51.307, p < 0.05). The outcome was lethal in 67/395 (17%) patients; 55% of them had chorioamnionitis (chi2 = 2.421, p > 0.05). Lethal outcome ensued in 54/132 (41%) infants from the first gestational age group; 30/54 (55%) were born from pregnancies complicated by chorioamnionitis. In comparison with the control group, mortality was significantly higher in the group of premature infants with gestation < or = 28 weeks whose placentas showed chorioamnionitis (chi2 = 7.645, p < 0.01). EONS was probable or confirmed in 100/395 (25%) infants; in 66/100 (66%) infants pregnancy was complicated by chorioamnionitis (chi2 = 22.396, p < 0.01). BPD developed in 25/395 (6%) infants; in 12/25 (48%) infants placentas showed chorioamnionitis (chi2 = 0.022, p > 0.05). In conclusion, premature neonates from pregnancies complicated by chorioamnionitis are more often born at < or = 28 weeks of gestation. Chorioamnionitis in neonates whose gestation is < or = 28 weeks leads to a significantly higher rate of mortality than in neonates with a longer gestation period. A greater incidence of EONS was proven in the group of infants with chorioamnionitis. The difference between the incidence of BPD in preterm infants born from pregnancies complicated by chorioamnionitis and the control group was not significant.