The association of chorioamnionitis with preterm delivery

Area of Science:

• Obstetrics and Gynecology
• Perinatal Medicine
• Infectious Disease

Background:

• Preterm delivery is a major cause of neonatal morbidity and mortality.
• The association between chorioamnionitis and preterm birth is recognized, but the proportion attributable to this infection requires further elucidation.

Purpose of the Study:

• To determine the proportion of preterm deliveries statistically attributable to histopathologic chorioamnionitis.
• To investigate the clinical presentation of histopathologic chorioamnionitis and its association with preterm delivery.

Main Methods:

• Prospective examination of placentas from 2774 women delivering at Johns Hopkins Hospital in 1980.
• Analysis of preterm delivery rates based on the presence or absence of chorioamnionitis and premature rupture of membranes (PROM).
• Logistic regression analysis to control for confounding variables.

Main Results:

• Preterm delivery incidence was 5.4% without chorioamnionitis or PROM, 11.9% with chorioamnionitis alone, and 56.7% with both conditions.
• Approximately 25% of preterm deliveries were statistically attributable to histopathologic chorioamnionitis.
• Maternal antepartum fever (8.1%) and neonatal sepsis (3.3%) were infrequent in cases of histopathologic chorioamnionitis.

Conclusions:

• Histopathologic chorioamnionitis is a significant contributor to preterm delivery, accounting for approximately 25% of cases.
• Occult antepartum genital tract infections, indicated by histopathologic chorioamnionitis, are an important cause of preterm delivery.
• The clinical signs of chorioamnionitis are often absent, underscoring the importance of subclinical infection in preterm birth.