Mild to Moderate, but Not Minimal or Severe, Acute Histologic Chorioamnionitis or Intra-Amniotic Inflammation Is Associated with a Decrease in Respiratory Distress Syndrome of Preterm Newborns without Fetal Growth Restriction

Abstract

Background: Acute histologic chorioamnionitis (acute-HCA) is known to be associated with a decreased risk of respiratory distress syndrome (RDS) in newborns. However, there is no information about whether the severity of acute-HCA or intra-amniotic inflammation (IAI) is associated with the development of RDS. Objectives: To assess the relationship between the severity of acute-HCA or IAI and the development of RDS in preterm newborns due to preterm labor and intact membranes (PTL) or preterm premature rupture of membranes (preterm-PROM) without fetal growth restriction (FGR). Methods: The frequency of RDS was examined in 378 singleton preterm neonates (24.5-34 weeks' gestation) due to PTL or preterm-PROM without FGR. Patients were divided into 4 groups according to the severity of acute-HCA (i.e. total grade: minimal, 1; mild, 2; moderate, 3-4; severe, 5-6) or IAI (i.e. amniotic fluid MMP-8: minimal, 23-100 ng/ml; mild, 100-400 ng/ml; moderate, 400-800 ng/ml; severe, ≥800 ng/ml). Amniotic fluid MMP-8 was measured in 196 patients delivered within 7 days of amniocentesis. Results: Mild to moderate, but not minimal or severe, acute-HCA (minimal, 24%; mild, 13%; moderate, 19%; severe, 41%; preterm-reference group, 26%) or IAI (minimal, 24%; mild, 11%; moderate, 17%; severe, 25%; preterm reference group, 23%) was associated with a significant decrease in RDS as compared with the preterm reference group (each for p < 0.05 after the adjustment of gestational age at delivery, antenatal corticosteroid use, newborn gender, cesarean delivery and preterm-PROM as a cause of preterm birth). Conclusions: Mild to moderate, but not minimal or severe, acute-HCA or IAI is associated with a significant decrease in RDS among preterm neonates due to PTL or preterm-PROM without FGR.

Placenta, secret witness of infant morbidities: the relationship between placental histology and outcome of the premature infant

“…RDS were similar among the groups. Current evidence has shown the higher risk of RDS in infants with placental abruption, and it is already known that CA decreases the risk of RDS (36,37). In contrast, we did not find any relationship between CA and risk of RDS (26,38).…”

Gastric fluid versus amniotic fluid analysis for the identification of intra-amniotic infection due toUreaplasmaspecies

“…Intra-amniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 (MMP-8) concentration (>23 ng/mL), as previously reported 15, 146–155 . Other studies showed that amniotic fluid MMP-8 concentration is a sensitive and specific index of intra-amniotic inflammation 151, 156–166 and correlates with an amniotic fluid white blood cell count 156, 158, 159 .…”

FGR in the setting of preterm sterile intra‐uterine milieu is associated with a decrease in RDS

“…RDS was diagnozed in the presence of an increase in oxygen requirement (FiO 2 >0.4), respiratory distress symptoms, radiological findings (i.e., reticulogranular pattern and/or air bronchogram), and laboratory findings (i.e., PaO 2 less than 50 mmHg with room air, or a necessity for additional oxygen to maintain a PaO 2 greater than 50 mmHg, if arterial sampling performed) when other causes of respiratory distress was absent according to previously published criteria …”

“…An ideal preterm reference group for the comparison with preterm FGR group should include cases without FGR in the setting of acute inflammation‐free placenta. Moreover, the selection of an adequate preterm reference group is essential for the RDS research in preterm gestations because fetal lung maturation may be accelerated in preterm neonates born to mothers with intra‐uterine infection or inflammation although some human studies do not demonstrate this relationship between acute‐HCA and RDS …”