Compromised chorionic villous vascularization in idiopathic second trimester fetal loss

For normal fetal growth and development a well-developed chorionic villous vascularization is essential.

The aim of this study is to investigate whether idiopathic second trimester fetal loss is associated with an underdeveloped chorionic villous vascularization.

38 placentas after late miscarriage, classified as idiopathic fetal loss (IFL, n=16) or as fetal loss due to intrauterine infection (IUI, n=22) were collected. After CD34 immunohistochemical staining the villous stromal area, number of villous vessels, vascular area and vascular area density (central, peripheral and total) were measured in randomly selected immature intermediate villi.

The mean gestational age was 19+4 weeks for the IFL group and 20+6 weeks for the IUI group. After controlling for gestational age, we found no differences in fetal weight, placental weight, villous stromal area, number of vessels and central vascular features. The mean peripheral vascular area and peripheral vascular area density were, after adjusting for gestational age, reduced in the IFL group.

Idiopathic second trimester fetal loss is associated with a reduced peripheral chorionic villous vascularization. We hypothesize that in these cases, placentation is already disturbed in first trimester of pregnancy, leading to a reduced materno-fetal interface in second trimester, thus to early postplacental fetal hypoxia and fetal death.