This is the birth sac that needs to be removed so the baby can start to breathe. If you are talking about the sac that shows on an ultrasound, this is the amniotic sac that contains the 'waters' and is absolutely necessary for the growth of the baby. It is the same thing that the answer above mentions.
The pink sack is called the placenta.
placenta
blood does not pass across the placenta
Yes your blood supply is shared with your baby though the placenta.
Placenta
False- The placenta supplies the baby with the mother's blood during development.
After birthing the baby, you will then birth the placenta. This is the 3rd stage of labor and is also referred to as the afterbirth. The afterbirth can take a few minutes up to a half an hour.
The umbilical cord carries blood between the fetus and the placenta. It contains two arteries and one vein that transport oxygen and nutrients to the fetus and remove waste products.
a sack of a quarterback behind the line of scrimage, that is a sack
Actually, the bleeding behind the placenta at 7 weeks gestation is called a "subchorionic" hematoma. This happens sometimes in pregnancies when the fetus attaches to the uterus. This is not necessarily a primary indication of a placental abruption and most pregnancies with subchorionic bleeds resolve after a few weeks
The umbilical vein carries oxygenated blood from the fetus to the placenta for nutrient and oxygen exchange.
Nutrients, oxygen, and waste are exchanged between the fetus and the mother through the placenta, a temporary organ that develops during pregnancy. The mother's blood containing nutrients and oxygen passes through the placenta, where it comes into close contact with the fetal blood vessels. Through diffusion and active transport processes, nutrients and oxygen are transferred from the mother's blood to the fetal blood, while waste products such as carbon dioxide are transferred from the fetal blood to the mother's blood for elimination.