Chorioamnionitis overview

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Epidemiology and Demographics
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Adnan Ezici, M.D[2]

Overview

Chorioamnionitis is an inflammatory condition of pregnancy affecting the uterus. It is a bacterial infection of the amniotic sac and the surrounding amniotic fluid. Chorioamnionitis is extremely dangerous to both the mother and fetus and is the most common cause of premature labor. Chorioamnionitis may be classified into several subtypes based on the presentation of the patient, the type of infiltrating cells, anatomical regions infiltrated by neutrophils (stage), and the intensity of inflammation (grade). Chorioamnionitis is an inflammatory condition of fetal membranes which is usually caused by infectious etiology. The opaque appearance of fetal membranes is a characteristic gross pathologic finding of chorioamnionitis. neutrophilic infiltration of the amniotic cavity and/or chorionic plate is the characteristic microscopic finding of chorioamnionitis. Chorioamnionitis may be caused by either bacterial, fungal, or viral microorganisms. Chorioamnionitis must be differentiated from other conditions that cause maternal fever, abdominal pain, or maternal/fetal tachycardia such as epidural-related fever, extrauterine infections, and noninfectious conditions characterized by abdominal pain. Epidural-related fever should be considered in patients with epidural anesthesia who have low grade fever without maternal/fetal tachycardia during the intrapartum period. Extrauterine infections should be considered in patients with fever and abdominal pain. And lastly, noninfectious conditions such as placental abruption should be considered in patients with abdominal pain in the absence of fever. The prevalence of chorioamnionitis was estimated to be approximately 4,000 cases per 100,000 individuals worldwide. Chorioamnionitis more commonly affects individuals < 18 years of age. Gestational age is also a strong predictor of chorioamnionitis with increased prevalence in people who delivered between 21 and 24 weeks of gestation. Male infants are more commonly affected than females. Chorioamnionitis usually affects individuals of Hispanics and Asian/Pacific Islanders. Common risk factors in the development of chorioamnionitis include preterm premature rupture of membranes (PPROM), prematurity, nulliparity, prolonged labor and rupture of membranes, multiple digital vaginal examinations, meconium stained amniotic fluid, internal fetal monitoring, epidural anesthesia, immunocompromised state, maternal behavioral conditions, and infections. Clinical findings associated with chorioamnionitis include maternal fever, uterine tenderness, purulent/foul-smelling amniotic fluid, maternal/fetal tachycardia. Common fetal complications of chorioamnionitis include preterm birth, neonatal sepsis, neurologic complications, respiratory complications. Common maternal complications of chorioamnionitis include maternal sepsis, infections, and labor-related complications (e.g., cesarean section, postpartum hemorrhage, etc.). There is no single diagnostic study of choice for the diagnosis of chorioamnionitis, but chorioamnionitis can be diagnosed based on the clinical presentation, laboratory findings, and/or histopathologic evaluation. The diagnosis of clinical chorioamnionitis is solely based on clinical features include maternal fever, uterine tenderness, maternal/fetal tachycardia, and foul-smelling/purulent amniotic fluid. And the gold standard (test) for the diagnosis of chorioamnionitis is a microbiological culture of the amniotic fluid. Common physical examination findings of chorioamnionitis include fever, abdominal pain, uterine tenderness, tachycardia, and foul-smelling vaginal discharge. Laboratory findings consistent with the diagnosis of chorioamnionitis include maternal leukocytosis, left shift or elevated band count, amniotic fluid findings (e.g., positive amniotic fluid microbiological culture results, bacteria or white blood cells on gram stain, decreased glucose level, elevated IL-6 level, etc.), and histologic findings such as neutrophilic infiltration of chorioamniotic membranes. There are no ECG findings associated with chorioamnionitis. There are no x-ray findings associated with chorioamnionitis. There are no ultrasound findings associated with chorioamnionitis. However, an ultrasound may be helpful in the diagnosis of complications of chorioamnionitis, which include postpartum hemorrhage, pelvic abscesses, endomyometritis, intraventricular hemorrhage, periventricular leukomalacia, respiratory distress syndrome, and bronchopulmonary dysplasia. There are no CT scan findings associated with chorioamnionitis. However, a CT scan may be helpful in the diagnosis of complications of chorioamnionitis, which include pelvic infections and abscesses, adrenal abscesses, and subphrenic abscess. There are no MRI findings associated with chorioamnionitis. However, an MRI may be helpful in the diagnosis of complications of chorioamnionitis, which include spontaneous preterm delivery, white matter injury (WMI), and intraventricular hemorrhage (IVH). Magnetic resonance spectroscopy(MRS) may be helpful for the detection of neuroinflammation during histologic chorioamnionitis. Furthermore, it may suggest a poor neurodevelopmental outcome (e.g. motor development, cognitive development, etc.) in these infants. There are no other diagnostic studies associated with chorioamnionitis. Antimicrobial therapy is indicated among patients with chorioamnionitis. The preferred regimen is a combination of ampicillin and gentamicin. Supportive therapy, such as antipyretics, may also be used. Surgical intervention is not recommended for the management of chorioamnionitis. Effective measures for the primary prevention of chorioamnionitis include induction of labor after 34 weeks of gestation and administration of prophylactic antimicrobial therapy in the presence of preterm premature rupture of membranes (PPROM). There are no established measures for the secondary prevention of chorioamnionitis.

Classification

Chorioamnionitis may be classified into several subtypes based on the presentation of the patient, the type of infiltrating cells, anatomical regions infiltrated by neutrophils (stage), and the intensity of inflammation (grade).

Pathophysiology

Chorioamnionitis is an inflammatory condition of fetal membranes which is usually caused by infectious etiology. The opaque appearance of fetal membranes is a characteristic gross pathologic finding of chorioamnionitis. neutrophilic infiltration of the amniotic cavity and/or chorionic plate is the characteristic microscopic finding of chorioamnionitis.

Causes

Chorioamnionitis may be caused by either bacterial, fungal, or viral microorganisms.

Differentiating Chorioamnionitis from Other Diseases

Chorioamnionitis must be differentiated from other conditions that cause maternal fever, abdominal pain, or maternal/fetal tachycardia such as epidural-related fever, extrauterine infections, and noninfectious conditions characterized by abdominal pain. Epidural-related fever should be considered in patients with epidural anesthesia who have low grade fever without maternal/fetal tachycardia during the intrapartum period. Extrauterine infections should be considered in patients with fever and abdominal pain. And lastly, noninfectious conditions such as placental abruption should be considered in patients with abdominal pain in the absence of fever.

Epidemiology and Demographics

The prevalence of chorioamnionitis was estimated to be approximately 4,000 cases per 100,000 individuals worldwide. Chorioamnionitis more commonly affects individuals < 18 years of age. Gestational age is also a strong predictor of chorioamnionitis with increased prevalence in people who delivered between 21 and 24 weeks of gestation. Male infants are more commonly affected than females. Chorioamnionitis usually affects individuals of Hispanics and Asian/Pacific Islanders.

Risk Factors

Common risk factors in the development of chorioamnionitis include preterm premature rupture of membranes (PPROM), prematurity, nulliparity, prolonged labor and rupture of membranes, multiple digital vaginal examinations, meconium stained amniotic fluid, internal fetal monitoring, epidural anesthesia, immunocompromised state, maternal behavioral conditions, and infections.

Natural History, Complications, and Prognosis

Clinical findings associated with chorioamnionitis include maternal fever, uterine tenderness, purulent/foul-smelling amniotic fluid, maternal/fetal tachycardia. Common fetal complications of chorioamnionitis include preterm birth, neonatal sepsis, neurologic complications, respiratory complications. Common maternal complications of chorioamnionitis include maternal sepsis, infections, and labor-related complications (e.g., cesarean section, postpartum hemorrhage, etc.)

Diagnosis

Diagnostic Study of Choice

There is no single diagnostic study of choice for the diagnosis of chorioamnionitis, but chorioamnionitis can be diagnosed based on the clinical presentation, laboratory findings, and/or histopathologic evaluation. The diagnosis of clinical chorioamnionitis is solely based on clinical features include maternal fever, uterine tenderness, maternal/fetal tachycardia, and foul-smelling/purulent amniotic fluid. And the gold standard (test) for the diagnosis of chorioamnionitis is a microbiological culture of the amniotic fluid.

History and Symptoms

The hallmark of chorioamnionitis is maternal fever. The presence of uterine tenderness, purulent/foul-smelling amniotic fluid, and maternal/fetal tachycardia is suggestive of chorioamnionitis.

Physical Examination

Common physical examination findings of chorioamnionitis include fever, abdominal pain, uterine tenderness, tachycardia, and foul-smelling vaginal discharge.

Laboratory Findings

Laboratory findings consistent with the diagnosis of chorioamnionitis include maternal leukocytosis, left shift or elevated band count, amniotic fluid findings (e.g., positive amniotic fluid microbiological culture results, bacteria or white blood cells on gram stain, decreased glucose level, elevated IL-6 level, etc.), and histologic findings such as neutrophilic infiltration of chorioamniotic membranes.

Electrocardiogram

There are no ECG findings associated with chorioamnionitis.

X-ray

There are no x-ray findings associated with chorioamnionitis.

Echocardiography and Ultrasound

There are no ultrasound findings associated with chorioamnionitis. However, an ultrasound may be helpful in the diagnosis of complications of chorioamnionitis, which include postpartum hemorrhage, pelvic abscesses, endomyometritis, intraventricular hemorrhage, periventricular leukomalacia, respiratory distress syndrome, and bronchopulmonary dysplasia.

CT scan

There are no CT scan findings associated with chorioamnionitis. However, a CT scan may be helpful in the diagnosis of complications of chorioamnionitis, which include pelvic infections and abscesses, adrenal abscesses, and subphrenic abscess.

MRI

There are no MRI findings associated with chorioamnionitis. However, an MRI may be helpful in the diagnosis of complications of chorioamnionitis, which include spontaneous preterm delivery, white matter injury (WMI), and intraventricular hemorrhage (IVH).

Other Imaging Findings

Magnetic resonance spectroscopy(MRS) may be helpful for the detection of neuroinflammation during histologic chorioamnionitis. Furthermore, it may suggest a poor neurodevelopmental outcome (e.g. motor development, cognitive development, etc.) in these infants.

Other Diagnostic Studies

There are no other diagnostic studies associated with chorioamnionitis.

Treatment

Medical Therapy

Antimicrobial therapy is indicated among patients with chorioamnionitis. The preferred regimen is a combination of ampicillin and gentamicin. Supportive therapy, such as antipyretics, may also be used.

Surgery

Surgical intervention is not recommended for the management of chorioamnionitis.

Primary Prevention

Effective measures for the primary prevention of chorioamnionitis include induction of labor after 34 weeks of gestation and administration of prophylactic antimicrobial therapy in the presence of preterm premature rupture of membranes (PPROM).

Secondary Prevention

There are no established measures for the secondary prevention of chorioamnionitis.