Clinical meaning
Chorioamnionitis is an acute infection of the amniotic fluid, membranes, placenta, and/or decidua, most commonly caused by ascending polymicrobial bacteria from the lower genital tract (Ureaplasma urealyticum, Mycoplasma hominis, GBS, E. coli, anaerobes). Prolonged rupture of membranes allows bacterial colonization of the amniotic cavity. The inflammatory response involves neutrophil infiltration of the chorion and amnion, release of pro-inflammatory cytokines (IL-1, IL-6, TNF-α), and prostaglandin production that stimulates uterine contractions. Fetal exposure causes fetal inflammatory response syndrome (FIRS) with risks of neonatal sepsis, pneumonia, and neurodevelopmental injury.
Diagnosis & workup
Diagnostics & workup: - Maternal fever ≥ 39°C (single) or ≥ 38°C on two readings 30 min apart - Maternal tachycardia > 100 bpm - Fetal tachycardia > 160 bpm - Fundal tenderness on palpation - Purulent or foul-smelling amniotic fluid - Maternal WBC > 15,000 (less specific in labor) - Amniocentesis for glucose, Gram stain, culture (definitive but rarely needed) - CRP and procalcitonin elevation