Clinical chorioamnionitis at term III: how well do clinical criteria perform in the identification of proven intra-amniotic infection?
OBJECTIVE
The diagnosis of clinical chorioamnionitis is based on a combination of signs [fever, maternal or fetal tachycardia, foul-smelling amniotic fluid (AF), uterine tenderness and maternal leukocytosis]. Bacterial infections within the amniotic cavity are considered the most frequent cause of clinical chorioamnionitis and an indication for antibiotic administration to reduce maternal and neonatal morbidity. Recent studies show that only 54% of patients with the diagnosis of clinical chorioamnionitis at term have bacteria in the AF and evidence of intra-amniotic inflammation. The objective of this study was to examine the performance of the clinical criteria for the diagnosis of chorioamnionitis to identify patients with microbial-associated intra-amniotic inflammation (also termed intra-amniotic infection).


METHODS
This retrospective cross-sectional study included 45 patients with the diagnosis of clinical chorioamnionitis at term, whose AF underwent analysis for: 1) the presence of microorganisms using both cultivation and molecular biologic techniques [polymerase chain reaction (PCR) with broad primers], and 2) interleukin (IL)-6 concentrations by enzyme-linked immunosorbent assay. The diagnostic performance (sensitivity, specificity, accuracy, and likelihood ratios) of each clinical sign and their combination to identify clinical chorioamnionitis were determined using microbial-associated intra-amniotic inflammation [presence of microorganisms in the AF using cultivation or molecular techniques and elevated AF IL-6 concentrations (≥2.6 ng/mL)] as the gold standard.


RESULTS
The accuracy of each clinical sign for the identification of microbial-associated intra-amniotic inflammation (intra-amniotic infection) ranged between 46.7% and 57.8%. The combination of fever with three or more clinical criteria did not substantially improve diagnostic accuracy.


CONCLUSIONS
In the presence of a fever during labor at term, signs used to diagnose clinical chorioamnionitis do not accurately identify the patient with proven intra-amniotic infection (i.e., those with microorganisms detected by culture or molecular microbiologic techniques and an associated intra-amniotic inflammatory response).
Roberto
R
Romero
Piya
P
Chaemsaithong
Steven J
SJ
Korzeniewski
Juan P
JP
Kusanovic
Nikolina
N
Docheva
Alicia
A
Martinez-Varea
Ahmed I
AI
Ahmed
Bo Hyun
BH
Yoon
Sonia S
SS
Hassan
Tinnakorn
T
Chaiworapongsa
Lami
L
Yeo
D000293:Adolescent; D000328:Adult; D000653:Amniotic Fluid / Q000276:immunology / Q000382:microbiology; D002821:Chorioamnionitis / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D018836:Inflammation Mediators / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D011247:Pregnancy; D012189:Retrospective Studies; D055815:Young Adult
C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6