{
 "topic": "Chorioamnionitis",
 "slug": "chorioamnionitis",
 "category_id": 15851,
 "summary": "Chorioamnionitis / Triple I: clinical diagnostic criteria, GBS/E. coli as the key neonatal pathogens, and the tiered newborn evaluation pathway based on gestational age and clinical appearance.",
 "written_by": "claude-sonnet",
 "references": [
  {
   "title": "Kliegman R. Nelson Textbook of Pediatrics 2-Volume Set 22ed 2024",
   "author": null,
   "pages": [
    1158,
    1159,
    1167
   ]
  },
  {
   "title": "MedStudy Pediatrics Core 11th Edition 2024-2025",
   "author": null,
   "pages": [
    16,
    19,
    58
   ]
  },
  {
   "title": "Pediatric Pulmonology",
   "author": "American Academy of Pediatrics Section on Pediatric Pulmonology and Sleep Medicine;Michael J Light;Kristin Van Hook;",
   "pages": [
    562
   ]
  },
  {
   "title": "Cover",
   "author": "Vitalsource Download",
   "pages": [
    1025
   ]
  },
  {
   "title": "Zitelli and Davis' Atlas of Pediatric Physical Diagnosis: Expert Consult - Online",
   "author": null,
   "pages": [
    76,
    77
   ]
  },
  {
   "title": "Pediatric Board Study Guide",
   "author": null,
   "pages": [
    52
   ]
  },
  {
   "title": "Gomella's Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs, Eighth Edition",
   "author": "Tricia Lacy Gomella, Fabien G. Eyal and Fayez Bany-Mohammed",
   "pages": [
    1114,
    1209,
    1215
   ]
  }
 ],
 "short": [
  {
   "title": "In short",
   "content": "- Chorioamnionitis is intrauterine inflammation/infection, classically from microbial invasion of amniotic fluid, most often following prolonged (18 hours or more) rupture of membranes - though it can occur with intact or briefly ruptured membranes.\n- Clinical diagnosis requires maternal fever (commonly defined as 39.0C or higher) plus at least one of: fetal tachycardia (over 160 bpm for more than 10 minutes), maternal WBC over 15,000/uL (without steroids), purulent fluid from the cervical os, or biochemical/microbiologic evidence of amniotic fluid infection.\n- The preferred modern term is \"intrauterine inflammation or infection at birth\" (Triple I), or \"intraamniotic infection\" per ACOG, replacing the older, imprecise \"chorioamnionitis\" label.\n- Histologic chorioamnionitis rate is inversely related to gestational age at birth and directly related to duration of membrane rupture; prematurity (under 37 weeks) carries a greater risk of early-onset sepsis, especially from group B Streptococcus.\n- Fetal/neonatal infection is most commonly caused by group B Streptococcus and Escherichia coli.\n- Chorioamnionitis increases the risk of neonatal sepsis, but most exposed infants do not develop sepsis.\n- Chorioamnionitis predisposes to preterm birth and has been proposed as a bronchopulmonary dysplasia (BPD) risk factor; evidence in humans is inconclusive overall, though preterm infants with respiratory tract colonization by Ureaplasma species (the most common organism cultured in chorioamnionitis) show increased risk of supplemental oxygen need at 28 days and 36 weeks postmenstrual age.\n- Diagnosis can only be histologically confirmed via placental pathology (\"histological chorioamnionitis\"), even though the bedside diagnosis is clinical (\"clinical chorioamnionitis\").\n- Management: early delivery, supportive care, and maternal antibiotics; the newborn is observed in the nursery for sepsis signs, with a limited evaluation (blood culture, CBC with differential/platelets at birth and/or 6-12 hours) for a well-appearing infant, escalating to full sepsis work-up and antibiotics if signs of illness develop.\n"
  }
 ],
 "long": [
  {
   "title": "Definition",
   "content": "Chorioamnionitis classically refers to microbial invasion of amniotic fluid, often resulting from prolonged rupture of the chorioamniotic membranes (conventionally 18 hours or more), though infection can also occur with apparently intact membranes or a brief duration of rupture. The clinical syndrome includes maternal fever with or without local or systemic signs: uterine tenderness, foul-smelling vaginal discharge/amniotic fluid, maternal leukocytosis, and maternal and/or fetal tachycardia. It may also be entirely asymptomatic, identified only by amniotic fluid analysis or placental pathology. Because the term does not capture the full spectrum of inflammatory and infectious processes involved, nor other affected intrauterine structures such as the decidua, and because it has led to variable clinical practice with many well newborns exposed unnecessarily to antimicrobials, the preferred modern term is intrauterine inflammation or infection at birth (abbreviated Triple I); the American College of Obstetricians and Gynecologists instead endorses \"intraamniotic infection.\"\n"
  },
  {
   "title": "Diagnostics",
   "content": "Chorioamnionitis/Triple I is a clinical diagnosis. Commonly cited criteria require maternal fever (variably defined, with 39.0C or higher used in some criteria) plus at least one of: fetal tachycardia (greater than 160 bpm for more than 10 minutes), maternal leukocytosis (white blood cell count over 15,000/uL in the absence of corticosteroids), purulent fluid from the cervical os, or biochemical or microbiologic evidence of amniotic fluid infection. On gross placental examination, the affected membranes lose their normal sheen and translucency, appearing gray, yellow, or opaque with yellowish discoloration; microscopic examination can confirm inflammation. True confirmation is only possible histologically (\"histological chorioamnionitis\"), even though the diagnosis made at the bedside is a clinical one (\"clinical chorioamnionitis\"), and clinical signs can be nonspecific.\n"
  },
  {
   "title": "Etiology",
   "content": "Fetal/neonatal infection associated with chorioamnionitis is most commonly caused by group B Streptococcus and Escherichia coli. Other recognized maternal peripartum risk factors for early-onset neonatal sepsis include urinary tract infection (especially GBS bacteriuria), rectovaginal GBS colonization, and perineal E. coli colonization. Ureaplasma species are the most commonly cultured organisms in chorioamnionitis overall.\n"
  },
  {
   "title": "Epidemiology",
   "content": "The rate of histologic chorioamnionitis is inversely related to gestational age at birth (more common with greater prematurity) and directly related to the duration of membrane rupture. Prematurity (under 37 weeks) carries a greater risk of early-onset sepsis, particularly from GBS, when chorioamnionitis is present.\n"
  },
  {
   "title": "Clinical Significance for the Neonate",
   "content": "Chorioamnionitis increases the risk of neonatal sepsis, but most infants exposed to chorioamnionitis do not go on to develop sepsis. Chorioamnionitis also predisposes to preterm birth and has been proposed as a risk factor for bronchopulmonary dysplasia (BPD); in animal models, chorioamnionitis arrests lung alveolar and vascular development, producing a BPD-like phenotype. However, human evidence is inconclusive: a 2011 meta-analysis found increased BPD risk in preterm infants born to mothers with histologically (but not clinically) diagnosed chorioamnionitis, but this association lost statistical significance after adjusting for confounders. A separate meta-analysis of 39 studies found that preterm infants with respiratory tract colonization by Ureaplasma species were at increased risk of needing supplemental oxygen at 28 days and at 36 weeks postmenstrual age, suggesting the causative organism may matter more than the chorioamnionitis diagnosis itself.\n"
  },
  {
   "title": "Management",
   "content": "Management of the pregnancy includes early delivery, supportive care, and antibiotic administration to the mother. The newborn is observed in the newborn nursery for signs of sepsis, with sepsis work-up and antibiotics initiated if such signs develop. A well-appearing infant of any gestational age born to a mother with chorioamnionitis requires at least a limited evaluation: blood culture (at birth) and complete blood count with differential and platelets (at birth and/or at 6-12 hours of life); some experts specifically recommend the CBC with differential and platelets at 6-12 hours. If gestational age is 37 weeks or more, home observation after 24 hours may be appropriate provided other discharge criteria are met, medical care access is readily available, and a caregiver able to comply with home observation instructions will be present; otherwise, the infant should be observed in hospital for at least 48 hours until discharge criteria are met. Where a structured clinical observation approach is used instead of universal laboratory testing, centers must establish serial, structured, documented physical assessments with clear criteria for escalation to evaluation and empirical antibiotics; identifying an initially well-appearing infant who later develops clinical illness under this approach is an anticipated outcome, not a failure of care, and a limited evaluation (CBC, CRP) at 6 hours of age may reasonably supplement structured clinical exams.\n"
  },
  {
   "title": "Complications",
   "content": "Diagnostic evaluation (blood cultures, with consideration of lumbar puncture) and presumptive antibiotic treatment are indicated for any symptomatic infant born to a mother with chorioamnionitis, given the risk of early-onset sepsis, meningitis, and pneumonia from the same causative organisms (chiefly GBS and E. coli).\n"
  }
 ],
 "clinical": [
  {
   "title": "Managing the Newborn Exposed to Chorioamnionitis",
   "content": "For a well-appearing infant of any gestational age born to a mother diagnosed with chorioamnionitis/Triple I, obtain at minimum a limited evaluation: blood culture at birth, plus a complete blood count with differential and platelets at birth and/or at 6-12 hours of life (some experts specifically favor the 6-12 hour timing to improve sensitivity). If the infant is 37 weeks or more gestation and remains well, home observation after 24 hours can be considered, but only if other discharge criteria are met, medical care is readily accessible, and a caregiver able to follow home observation instructions will be present; otherwise keep the infant in hospital for observation for at least 48 hours until discharge criteria are met. If signs of sepsis develop at any point - respiratory distress, temperature instability, poor perfusion, lethargy - proceed to a full diagnostic evaluation (including consideration of lumbar puncture) and start presumptive antibiotics rather than continuing observation alone. When a structured clinical-observation approach (rather than universal labs) is used at a given center, ensure serial, documented physical assessments occur with clear, predefined criteria for escalating to evaluation and treatment, and counsel families in advance that a later-developing illness in an initially well-appearing infant reflects the expected course of this monitoring strategy, not a care failure.\n"
  },
  {
   "title": "Interpreting the Chorioamnionitis Diagnosis Itself",
   "content": "Recognize that \"chorioamnionitis\" is diagnosed clinically at the bedside (maternal fever plus fetal tachycardia, maternal leukocytosis over 15,000/uL, purulent cervical os discharge, or biochemical/microbiologic evidence of infection) but can only be truly confirmed by placental histology after delivery - so a clinical diagnosis, even without histologic confirmation, is sufficient to trigger neonatal evaluation as above. Remember that prolonged rupture of membranes (18 hours or more) is the classic antecedent but is not required, and that most infants exposed to chorioamnionitis will not develop sepsis, which should inform proportionate rather than reflexively aggressive management of the well-appearing exposed newborn.\n"
  }
 ]
}