title: Twenty-four percent of patients with clinical chorioamnionitis in preterm gestations have no evidence of either culture-proven intraamniotic infection or intraamniotic inflammation.
abstract: Recent studies on clinical chorioamnionitis at term suggest that some patients with this diagnosis have neither intraamniotic infection nor intraamniotic inflammation. A false-positive diagnosis of clinical chorioamnionitis in preterm gestation may lead to unwarranted preterm delivery.
  
  
  
  We sought to determine the frequency of intraamniotic inflammation and microbiologically proven amniotic fluid infection in patients with preterm clinical chorioamnionitis.
  
  
  
  Amniocentesis was performed in singleton pregnant women with preterm clinical chorioamnionitis (<36 weeks of gestation). Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas and assayed for matrix metalloproteinase-8 concentration. Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture; intraamniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 concentration of >23 ng/mL. Nonparametric and survival techniques were used for analysis.
  
  
  
  Among patients with preterm clinical chorioamnionitis, 24% (12/50) had neither microbiologic evidence of intraamniotic infection nor intraamniotic inflammation. Microbial invasion of the amniotic cavity was present in 34% (18/53) and intraamniotic inflammation in 76% (38/50) of patients. The most common microorganisms isolated from the amniotic cavity were the Ureaplasma species. Finally, patients without microbial invasion of the amniotic cavity or intraamniotic inflammation had significantly lower rates of adverse outcomes (including lower gestational age at delivery, a shorter amniocentesis-to-delivery interval, acute histologic chorioamnionitis, acute funisitis, and significant neonatal morbidity) than those with microbial invasion of the amniotic cavity and/or intraamniotic inflammation.
  
  
  
  Among patients with preterm clinical chorioamnionitis, 24% had no evidence of either intraamniotic infection or intraamniotic inflammation, and 66% had negative amniotic fluid cultures, using standard microbiologic techniques. These observations call for a reexamination of the criteria used to diagnose preterm clinical chorioamnionitis.
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea.
authors.forename: Kyung Joon
authors.initials: KJ
authors.lastname: Oh
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Obstetrics and Gynecology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Republic of Korea.
authors.forename: Sun Min
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea.
authors.forename: Joon-Seok
authors.initials: JS
authors.lastname: Hong
authors.affiliation: Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development/National Institutes of Health/US Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI.
authors.forename: Eli
authors.initials: E
authors.lastname: Maymon
authors.affiliation: Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development/National Institutes of Health/US Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI.
authors.forename: Offer
authors.initials: O
authors.lastname: Erez
authors.affiliation: Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development/National Institutes of Health/US Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Panaitescu
authors.affiliation: Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development/National Institutes of Health/US Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI; Department of Immunology, Microbiology and Biochemistry, Wayne State University School of Medicine, Detroit, MI.
authors.forename: Nardhy
authors.initials: N
authors.lastname: Gomez-Lopez
authors.affiliation: Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development/National Institutes of Health/US Department of Health and Human Services, Bethesda, MD, and Detroit, MI; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI; Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI; Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI. Electronic address: prbchiefstaff@med.wayne.edu.
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: Yoonbh@snu.ac.kr.
authors.forename: Bo Hyun
authors.initials: BH
authors.lastname: Yoon
mesh_terms: D000328:Adult; D000649:Amniocentesis; D000650:Amnion / Q000382:microbiology; D000653:Amniotic Fluid / Q000201:enzymology / Q000382:microbiology; D001424:Bacterial Infections / Q000175:diagnosis / Q000453:epidemiology; D002821:Chorioamnionitis / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D015331:Cohort Studies; D005189:False Positive Reactions; D005260:Female; D005865:Gestational Age; D006801:Humans; D020784:Matrix Metalloproteinase 8 / Q000032:analysis; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis* / Q000453:epidemiology; D011256:Pregnancy Outcome; D047928:Premature Birth; D056910:Republic of Korea; D012189:Retrospective Studies; D014509:Ureaplasma / Q000302:isolation & purification
chemical_list: C488762:MMP8 protein, human; D020784:Matrix Metalloproteinase 8
keywords: amniocentesis; matrix metalloproteinase-8 (MMP-8); microbial invasion of the amniotic cavity (MIAC); pregnancy; preterm delivery