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 in early labor, likely resulting in a stillbirth. This is a serious condition called vasa previa.
Interesting! One of my twins had a velementous cord insertion. He graduates with a degree in electrical engineering next year.
Alot of blood for placenta and eclampsia by the lining of the placenta