Validation of diagnostic tests for histologic chorioamnionitis: Systematic review and meta-analysis

The aim of this study was to determine the diagnostic performance of different diagnostic tests for histologic chorioamnionitis in patients at more than 20 weeks of gestation.

A systematic search was carried out through MEDLINE, EMBASE, LILACS, CENTRAL and unpublished literature. Observational studies included with pregnant women (>20 weeks) with chorioamnionitis. The reference standard was the histopathological study of the placenta, umbilical cord and fetal membranes. Two independent researchers extracted data and performed a meta-analysis of diagnostic tests.

Twenty-nine articles were included. The studies provided evidence in the form of maternal clinical and serological tests; tests of vaginal fluid, amniotic fluid or the umbilical cord; fetal monitoring and ultrasound tests. To assess the performance of maternal serum CRP, 13 studies were included, showing a combined sensitivity of 68.7% (95%CI 58%-77%) and a combined specificity of 77.1% (95%CI 67%-84%). Maternal leukocytosis was evaluated in four publications, showing a combined sensitivity of 51% (95%CI 40%-62%) and a combined specificity of 65% (95%CI 50%-78%).

CRP and maternal leukocytosis, showed a low sensitivity and specificity. The sonographic evaluation of the fetal thymus is also more sensitive for the diagnosis of histologic chorioamnionitis than the fetal biophysical profile.