Chorioamnionitis

Chorioamnionitis refers to infection of the chorion and amnion during pregnancy.

Epidemiology

Chorioamnionitis affects an estimated 2-4% of term deliveries and 40-70% of preterm deliveries ¹.

Clinical presentation

Clinically, chorioamnionitis can present with the following maternal signs and symptoms ^1,2:

• fever
• abdominal pain / uterine tenderness
• raised white blood cell count (> 15 000 cells/mm³)
• purulent or foul vaginal discharge
• tachycardia

Pathology

Chorioamnionitis most frequently occurs due to ascending bacterial infection from the lower genital tract (vagina and cervix) in the setting of prolonged rupture of membranes (PROM) ¹. Other less common causes include the introduction of infection through invasive procedures such as amniocentesis and chorionic villus sampling ^1,2.

Risk factors

• premature rupture of membranes
• preterm premature rupture of membranes
• prolonged labor

Treatment and prognosis

Immediate initiation of intrapartum broad-spectrum antibiotics greatly reduces adverse maternal and fetal outcomes from chorioamnionitis ¹.

Differential diagnosis

Differentials that may be considered in the setting of maternal fever and/or abdominal pain include ²:

• pyelonephritis
• appendicitis
• pneumonia
• epidural-associated fever (in women with epidural catheter for analgesia)
• thrombophlebitis

Complications

• neonatal sepsis ¹
• increased risk of cerebral palsy ³