The fetus at risk: Chorioamnionitis

Abstract

Infection and inflammatory injury are the major threats during pregnancy. The extraembryonic tissues play important roles in protecting the fetus. From 10−12 days post conception (p.c.), yolk sack and allantoic vessels provide nutrition to the embryo. By 20 days conception p.c. fetal vessels are discernible in developing villi. They communicate with the embryo via a connecting stalk that later develops into the umbilical cord. By 40 days p.c. the embryo is completely surrounded by the amniotic cavity and attached via the umbilical cord to the hemo-monochorial placenta [1]. Upon complete adherence of the fetal membranes to the decidua at about 20 weeks of gestation, bacterial inflammation may directly penetrate the chorioamnion from any direction and contaminate the amniotic fluid [2, 3]. In high risk pregnancies the protective fetal chorioamnion and placental villi are challenged in multiple ways. These tissues respond by inflammation, producing mediators that may promote labor or affect the fetus in multiple ways. This chapter focuses only on the consequences of chorioamnionitis in the fetus comparing the affected fetuses to the gestation controls.