Chorioamnionitis

Invasion through a breached fortress wall

Picture a medieval fortress with a moat (the amniotic fluid), a sealed gate (the cervical mucus plug), and high walls (the amniotic membranes). Soldiers normally camp outside the moat—they are the vaginal bacteria that belong there. But when the gate breaks down (membranes rupture) or stays open too long (prolonged labor), those soldiers march across the moat and swarm the courtyard because nothing stops them anymore. The fortress guards (white blood cells) sound the alarm and rush to fight, making torches burn hotter (fever) and their hearts pound faster (tachycardia). The guards fight valiantly, but without the castle gate restored quickly and reinforcements (antibiotics) arriving fast, the infection spreads through the walls into the bloodstream-roads beyond, threatening the entire kingdom (sepsis). The longer the gate stays open, the more soldiers invade and multiply, and the harder it becomes to defend.