Chorioamnionitis

Chorioamnionitis, also known as intra-amniotic infection, is an infection of the fetal membranes—the chorion and amnion—and the amniotic fluid. It most often results from ascending bacterial infection of the lower genital tract during pregnancy or labor and is associated with placental and fetal membrane inflammation.

The condition is frequently polymicrobial. Common organisms include Group B Streptococcus and Escherichia coli, with anaerobes and other vaginal flora also implicated. Risk factors include prolonged rupture of membranes, preterm labor, multiple vaginal examinations during labor, intrauterine procedures, and maternal fever in labor.

Clinical presentation typically includes maternal fever and tachycardia, uterine tenderness, and foul-smelling amniotic fluid; fetal tachycardia and leukocytosis may be observed. Diagnosis is mainly clinical, supported by laboratory findings and, when available, analysis of amniotic fluid or placental tissue showing neutrophilic inflammation.

Treatment requires intrapartum antibiotics and delivery of the fetus if feasible. Common regimens include broad-spectrum antibiotics such as ampicillin plus gentamicin. Intrapartum management aims to prevent maternal sepsis and neonatal infection; neonates may require evaluation and empiric antibiotics.

Prognosis improves with prompt treatment but antenatal infection is associated with maternal sepsis, postpartum endometritis, and adverse neonatal outcomes, including sepsis and respiratory distress. Prevention focuses on reducing ascending infection, including intrapartum antibiotic prophylaxis for Group B Streptococcus carriers and minimizing prolonged rupture of membranes when possible.