Wednesday, February 28, 2007

Blood Test Explained...Rh??


If you just found out you're pregnant, one of the first - and most important - tests you should expect is a blood-type test. This basic test determines your blood type and Rh factor. Your Rh factor may play a role in your baby's health, so it's important to know this information early in your pregnancy.

What Is the Rh Factor?
People with different blood types have proteins specific to that blood type on the surfaces of their red blood cells. There are four blood types - A, B, AB, and O.

Each of the four blood types is additionally classified according to the presence of another protein on the surface of red blood cells that indicates the Rh factor. If you carry this protein, you are Rh positive. If you don't carry the protein, you are Rh negative.

Most people - about 85% - are Rh positive. But if a woman who is Rh negative and a man who is Rh positive conceive a baby, there is the potential for a baby to have a health problem. The baby growing inside the Rh-negative mother may have Rh-positive blood, inherited from the father. Approximately half of the children born to an Rh-negative mother and Rh-positive father will be Rh positive.

Rh incompatibility usually isn't a problem if it's the mother's first pregnancy because, unless there's some sort of abnormality, the fetus's blood does not normally enter the mother's circulatory system during the course of the pregnancy.

However, during delivery, the mother's and baby's blood can intermingle. If this happens, the mother's body recognizes the Rh protein as a foreign substance and can begin producing antibodies (protein molecules in the immune system that recognize, and later work to destroy, foreign substances) against the Rh proteins introduced into her blood.
Other ways Rh-negative pregnant women can be exposed to the Rh protein that might cause antibody production include blood transfusions with Rh-positive blood, miscarriage, and ectopic pregnancy.

Rh antibodies are harmless until the mother's second or later pregnancies. If she is ever carrying another Rh-positive child, her Rh antibodies will recognize the Rh proteins on the surface of the baby's blood cells as foreign, and pass into the baby's bloodstream and attack those cells. This can lead to swelling and rupture of the baby's red blood cells. A baby's blood count can get dangerously low when this condition, known as hemolytic or Rh disease of the newborn, occurs.

How Is Rh Disease of the Newborn Prevented and Treated?
In generations past, Rh incompatibility was a very serious problem. Fortunately, significant medical advances have been made to help prevent complications from Rh incompatibility and to treat any newborn affected by Rh disease.

Today, when a woman with the potential to develop Rh incompatibility is pregnant, doctors administer a series of two Rh immune-globulin shots during her first pregnancy. The first shot is given around the 28th week of pregnancy and the second within 72 hours after giving birth. Rh immune-globulin acts like a vaccine, preventing the mother's body from producing any potentially dangerous Rh antibodies that can cause serious complications in the newborn or complicate any future pregnancies.


1 comment:

Gombojav said...

So is David Rh negative or positive? That would determine if you really needed the shot or not.

It's a problem many times when people of different races conceive, but not as common when two people of the same race conceive.