Acute chorioamnionitis is a condition affecting pregnant individuals, characterized by inflammation or infection within the membranes and fluid surrounding the developing baby. This condition can arise during pregnancy, labor, or even after delivery.
Defining Acute Chorioamnionitis
Acute chorioamnionitis refers to an infection or inflammation of the fetal membranes and amniotic fluid. The name indicates the affected structures: “chorion” and “amnion” are the two membranes forming the amniotic sac, and “-itis” denotes inflammation. The chorion is the outer membrane, while the amnion is the inner membrane directly encasing the amniotic fluid. This fluid cushions the fetus and aids development. Acute chorioamnionitis occurs when bacteria from the vagina or rectum ascend into the uterus, infecting these membranes and the amniotic fluid. While often bacterial, it can also involve a sterile inflammatory response.
Identifying the Signs and Risk Factors
Acute chorioamnionitis is indicated by clinical signs and symptoms. A primary indicator is maternal fever, defined as at least 100.4°F (38.0°C). This may be accompanied by maternal tachycardia (heart rate over 100 bpm) or fetal tachycardia (baby’s heart rate consistently above 160 bpm for at least 10 minutes). Uterine tenderness (pain upon touching the uterus) and foul-smelling amniotic fluid or vaginal discharge also suggest this condition.
Several factors increase the likelihood of acute chorioamnionitis. Prolonged rupture of membranes, often referred to as “water breaking,” allows more time for bacteria to ascend into the uterus. Multiple vaginal examinations after membrane rupture can introduce bacteria and elevate the risk. Preterm labor and Group B Streptococcus colonization are additional contributing factors.
Diagnosis and Treatment Approaches
Diagnosing acute chorioamnionitis primarily relies on clinical assessment, although laboratory tests can provide supporting evidence. Healthcare providers often diagnose the condition based on the presence of maternal fever combined with at least one other sign, such as maternal or fetal tachycardia, uterine tenderness, or foul-smelling amniotic fluid. While a single symptom like maternal fever can be misleading, the combination of signs strengthens the diagnostic confidence.
Laboratory tests can further aid in confirming the diagnosis. Blood tests may reveal maternal leukocytosis, an elevated white blood cell count, which suggests an infection. Analysis of amniotic fluid, obtained through amniocentesis, can also be performed to identify bacteria or inflammatory markers, although this invasive procedure is often avoided due to the clinical nature of diagnosis.
Treatment for acute chorioamnionitis involves immediate medical intervention, primarily through antibiotic administration and often delivery of the baby. Broad-spectrum antibiotics are typically given to the mother to target the bacterial infection. Common antibiotic regimens include a combination of ampicillin and gentamicin, with clindamycin or metronidazole potentially added, especially if a cesarean delivery is performed. Delivery of the baby is often recommended to resolve the infection and prevent further complications for both the mother and the newborn.
Potential Acute Complications
Acute chorioamnionitis can lead to immediate complications for both the pregnant individual and the newborn. For the mother, potential acute issues include postpartum hemorrhage, which is excessive bleeding after childbirth. This can occur due to uterine atony, a condition where the uterus fails to contract adequately after delivery. Maternal sepsis, a severe and potentially life-threatening systemic infection, is another serious acute complication that can arise.
Newborns exposed to acute chorioamnionitis are also at risk for several immediate health problems. Neonatal sepsis, a blood infection in the newborn, is a significant concern. Respiratory distress syndrome, a breathing disorder affecting newborns, particularly those born prematurely, can also occur. Furthermore, the inflammation associated with chorioamnionitis has been linked to an increased risk of cerebral palsy due to its potential impact on fetal brain development.