Relationship of Amniotic Fluid Markers of Intra-Amniotic Infection With Histopathology in Cases of Preterm Labor With Intact Membranes

Abstract

OBJECTIVE:To evaluate the correlation of amniotic fluid (AF) markers (AFMs) of intra-amniotic infection with histopathologic findings in cases of preterm labor with intact membranes, between 22 and 36 weeks' gestation. STUDY DESIGN:We reviewed the charts of patients admitted in preterm labor with intact membranes between January 1993 and December 1996. Those having amniocentesis were identified, and AFMs were compared with histopathology in patients who delivered within 48 hours of the amniocentesis. The AFMs evaluated were glucose, polymorphonuclear leukocytes, Gram stain, and culture. All placentae were reviewed by a single pathologist blinded to the AF findings. Histologic evidence of acute inflammation was defined by findings of both subchorial intervillositis and marginating choriodeciduitis. The sensitivities, specificities, and positive and negative predictive values of the various AFMs were calculated. RESULTS:Of 556 women with intact membranes presenting in preterm labor, 181 (32.6%) had amniocentesis and 88 delivered within 48 hours of the amniocentesis. Histopathologic chorioamnionitis was seen in 53 patients (60.2%). The findings (with their sensitivity, specificity, and positive and negative predictive values) were: polymorphonuclear leukocytes at Ͼ10/ high-power field (22.6%, 97.2%, 92.3%, and 46.1%), positive Gram stain (26.4%, 94.6%, 87.5%, and 47.3%), culture (28.3%, 92.1%, 83.3%, and 47.9%), and glucose of Ͻ15 mg/dl (28.3%, 94.6%, 88.2%, and 47.9%), respectively. Using a receiver-operator characteristic curve for different levels of AF glucose, a glucose level of Ͻ20 mg/dl was the most sensitive AF predictor of histologic chorioamnionitis. CONCLUSION:Histopathologic evidence of chorioamnionitis was present in 60.2% of cases of preterm births due to preterm labor in women who at our institution were offered and accepted amniocentesis and subsequently delivered within 48 hours. AFMs may be useful predictors of histologic chorioamnionitis. The most efficient AFM for chorioamnionitis in this group of patients was glucose at Ͻ20 mg/dl.Histologic chorioamnionitis has been associated with preterm labor and preterm births. 1-3 Although histologic inflammation is suggestive of intra-amniotic microbial invasion, the results of the few studies available are inconsistent. In some of these studies, the microbial invasion was evaluated only in the placenta and not in the amniotic cavity. [3][4][5] Histologic chorioamnionitis has been strongly associated with positive cultures of the chorioamnion. 3 Only two previous studies have addressed the relationship of amniotic fluid (AF) microbiology to histopathologic inflammation. 6,7 The first study 6 was limited by the transcervical method of AF collection, for which there is an inherent risk of contamination. The membranes in this study were ruptured. The second study used AF culture as the only method of identifying microbial invasion of the AF. 7 The aim of this study was to determine the relationship of several AF markers (AFMs) of intra-amniotic infection (IA...

Clinical significance of histologic chorioamnionitis with a negative amniotic fluid culture in patients with preterm labor and premature membrane rupture

“…Several investigators have reported that the incidence of intra-amniotic inflammation (as assessed by a mass-restricted score or glucose level) was significantly higher in patients with HCA than in those without HCA, all of whom delivered within 48 hours of amniocentesis [9, 18]. In accordance with previous reports [9, 18], our results demonstrated that women with HCA who had negative AF culture results showed stronger intra-amniotic inflammatory response (elevated AF IL-6, IL-8, and MMP-9 levels) and a higher rate of intra-amniotic inflammation than those without HCA with negative AF culture.…”

Relationship between Antenatal Inflammation and Antenatal Infection Identified by Detection of Microbial Genes by Polymerase Chain Reaction

“…Chorioamnionitis was present in 60% of deliveries arising from pPROM and 40% of deliveries following preterm labor. Chorioamnionitis has previously been associated with 36 -60% of placentas resulting from preterm labor with intact membranes (14,16,47) compared with 42-80% of placentas after pPROM (15,45,48). Only a proportion of cases of chorioamnionitis have been associated with microbes isolated from either placenta (14) or amniotic fluid (16).…”

The prospects for multiple‐marker screening for preterm delivery: does transvaginal ultrasound of the cervix have a central role?

“…There are several studies associating direct and indirect evidence of intra-amniotic infections and spontaneous PTD [57][58][59][60][61] . The microorganisms that have been implicated include bacterial vaginosis, group B streptococcus, trichomonas vaginalis, mycoplasmas, fusobacteria and Ureaplasma urealyticum.…”