CIRCUMMARGINATE PLACENTA

The margin of the chorionic plate is raised thin rim of fibrous tissue. The transition from villous to membranous chorion occurs at some distance from the edge of the placenta.

Circummarginate placentae have no clinical significance.

The mamelonated appearance of the marginal chorionic plate is less pronounced in circummarginate placenta. The abnormal placental sonographic features disappear during the second half of the pregnancy (unlike circumvallate placenta), probably because the placenta can adapt to the stretching of the myometrium.