Introduction to intra-amniotic infection
Intra-amniotic infection (previously called chorioamnionitis) is an infection involving the amniotic fluid, placenta, fetus, fetal membranes or decidua. Most intra-amniotic infections are polymicrobial and caused by ascending cervicovaginal organisms (eg Streptococcus agalactiae [group B streptococcus], Enterobacteriaceae). Genital mycoplasmas are commonly isolated from patients with intra-amniotic infection, but the clinical significance of these organisms is uncertain. Rarely, intra-amniotic infection may arise from haematogenous spread of organisms from a maternal bacteraemia (eg Listeria monocytogenes 1) or as a direct result of an invasive procedure (eg amniocentesis).
Women with intra-amniotic infections often present with nonspecific signs of infection. Suspect intra-amniotic infection in a pregnant woman with any of the following features:
- fever (38°C or more) and ruptured membranes
- fever during labour (intrapartum fever), even if membranes are intact
- uterine tenderness
- purulent amniotic fluid.
If intra-amniotic infection is suspected, early consultation with an obstetrician is required for appropriate assessment and management. Complications of intra-amniotic infection include preterm labour and delivery, postpartum uterine atony with haemorrhage, maternal infections including endometritis, and neonatal morbidity and mortality related to prematurity and neonatal sepsis.