The Placenta  And Umbilical Cord

The placenta is a soft, round or oval organ that grows with your baby. At 10 weeks, it weighs about 12 g by the time your baby is born, it weighs about 1112 pounds (700 g).
When the early pregnancy implants in your uterus, the placenta grows and sends blood vessels into the uterine wall. These blood vessels carry nourishment and oxygen from your blood for your baby's use. Your baby's waste products pass back into your bloodstream through these vessels for disposal by your body.

We once believed the placenta acted as a barrier to all outside substances, but we now know this is not the case. In some instances, the placenta cannot keep your baby from being exposed to substances that you are exposed to or that you ingest. We know that alcohol, most medications, other substances (such as nicotine) and many vitamins and minerals cross the placenta to your baby. This is one reason women should avoid various substances during pregnancy.

The placenta is important to your pregnancy and remains so until the birth of your baby. At that time, when your uterus begins to shrink after your baby is born, the placenta detaches from it and is delivered on its own.

The Umbilical Cord
The umbilical cord is the connection between your baby and the placenta. It is usually about 24 inches (61cm) long. The cord is gray or white, coiled or lumpy, and contains two arteries that carry the baby's blood to the placenta, where it absorbs oxygen and nutrients. A vein in the umbilical cord carries blood and nutrients back to the baby.

Rarely knots form in an umbilical cord. Doctors believe knots form as the baby moves around early in pregnancy. A loop forms in the umbilical cord, and when the baby moves through the loop, a knot is completed. You can't do anything to prevent it.

You may have heard about saving blood from your baby's umbilical cord for future use. Umbilical-cord blood banking is not available everywhere. Since 1989, cord blood has been used as an alternative to bone-marrow transplants and to treat some forms of anemia (such as Fanconi's anemia), Wiskott-Aldrich syndrome, Hunter's syndrome, some forms of leukemia, neuroblastoma and breast cancer. Talk with your doctor about cord-blood banking if you are interested in learning more.