How does chorioamnionitis cause preterm birth? isnt the fetus protected my the amniotic sac and the mucus plug so that bacteria wont make its way up to the uterus and the membranes?

Definition: By usual definition chorioamnionitis germs enter from below. Microscopic leaks can occur in those membranes for a variety of reasons, including the fetal fingers/toes raking past/tearing the membrane. This can result in unrecognized leaking of amniotic fluid.If it leaks out germs can get in & the irritation triggers labor. Leaks dissolve any plug.