 |
 |
 |
 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
 |
 |
During the pre-operative medical review, one of the necessary screening tests is to check for a protein attached to the woman's red blood cells called an Rh factor. If her blood has this protein, then her blood type is Rh positive (+). If the woman's blood does not have this protein, then her blood type is Rh negative (-).
At least 85% of people, depending on their ethnic origin, are Rh+. Either type is perfectly normal, except when a woman is pregnant, it is important to determine her Rh factor.
When Rh- blood is exposed to Rh+ blood, perhaps through a transfusion, the Rh- blood builds up antibodies. These antibodies defend the Rh- blood from the Rh+ factor, which is seen as foreign. These antibodies then cause some red blood cells to be broken down and their products are spread through the body.