So transparent!! Membranous cord insertion and vasa previa (notice the vessels through the membranes) demonstrated on this fresh placenta shortly after delivery!! A velamentous umbilical cord is characterized by membranous umbilical vessels at the placental insertion site that are prone to compression and rupture, especially when they are located in the membranes covering the cervical os (vasa praevia). Normally, the blood vessels of the baby run from the middle of the placenta via the umbilical cord to the baby. Velamentous insertion means that the blood vessels, unprotected by Wharton's jelly, traverse the membranes before they come together into the umbilical cord. It's a condition in which the umbilical cord inserts on the chorioamniotic membranes rather than on the placental mass. Therefore, a variable segment of the umbilical vessels runs between the amnion and the chorion, losing the protection of the Wharton's jelly and hence are vulnerable to rupture. Rupture is especially likely if the vessels are near the cervix, in which case they may rupture prematurely in early labor. When membranes rupture prematurely, hemorrhage occurs with loss of fetal blood, likely resulting in a stillbirth. Photo credit @nachoptomasone
My ex-33 weeker preemie twin with a velamentous cord insertion turned 21 two days ago.