What would occur if a fetus's villi tissue ruptured?   the maternal tissue of the placenta would be damaged, causing bleeding. the maternal and fetal blood would mix, causing an immune reaction. the umbilical vein would be blocked, preventing waste export from the fetus. the umbilical artery would be blocked, preventing oxygen import to the fetus.

 If a fetus's villi tissue ruptured the maternal tissue of the placenta would be damaged, causing bleeding.

The placenta is developed in the uterus during the pregnancy. This structure provides oxygen and nutrients to the growing baby and removes waste products from the baby's blood.
The diagram clearly shows the position of placenta around the baby and is considered as its protection.