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Blood type is used to describe the proteins, or the absence of proteins, on blood cells, and although it may seem completely unrelated, blood type can actually be a risk factor for cerebral palsy in certain scenarios.
When a mother and her developing fetus have incompatible blood types, it can lead to disease in the baby, and potentially to severe jaundice that may cause the brain damage that can then cause cerebral palsy.
It is easy to check for blood types in the mother and baby after birth and for the possibility of Rh incompatibility during pregnancy. Preventative treatments can reduce the risk of an incompatibility harming the fetus or newborn. I
Blood type describes the characteristics of blood cells in a particular person. More specifically, the type describes the kinds of proteins, or lack of proteins, that a person has on their red blood cells. Blood is typed as ABO, but also by Rh factor. ABO blood types may be A, B, AB, or O. 
There are two proteins, which are known as antigens, represented by A and B. Someone with type A blood has A antigens on their red blood cells. B refers to B antigens, AB means the blood cells have both types of antigens, and O means that there are no antigens on the blood cells.
Rh blood type is positive or negative, written as Rh+ or Rh-. Positive means that a person’s blood has the Rh protein and negative means that the protein is absent. When ABO and Rh and described together, there are eight different blood types: A+, A-, B+, B-, AB+, AB-, O+, and O-. In other words, everyone has one of each type, from ABO and Rh.
Your blood type comes from your parents. You get one gene from your mother and one from your father for ABO and Rh and that combination determines your blood type. While there are four options for ABO, there are only two for Rh and positive is dominant.
If you get a positive Rh gene from one parent and negative from another, your body will produce the Rh protein and you are considered Rh+. Most people are Rh+.
Rh incompatibility occurs during pregnancy if the mother is Rh- and the baby is Rh+.  This is problematic because the mother’s body does not recognize the Rh protein and will treat it as a foreign substance. This occurs because the blood typing proteins are antigens, which attract immune system antibodies.
If there is a foreign antigen in the bloodstream, the immune system will create antibodies that attach to the antigens and signal an attack on them.
A mother’s antibodies circulate in the fetus to help it survive while the immune system develops, but when there is a blood type incompatibility, those antibodies may go on the attack. The fetus’s blood cells may also circulate into the mother, also prompting an attack.
This is not a very common problem since most people are Rh+. However, in about 13 percent of female partnerships, there is a risk that a pregnancy could result in an Rh incompatibility. These are partnerships in which the mother is Rh- and the father is either Rh+ or his Rh status is unknown.
Rh incompatibility between mother and fetus can cause a condition known as hemolytic disease of the newborn. Rh disease is estimated to occur in 2 out of every 100,000 births in the U.S.
A mother and child may also have an ABO blood type incompatibility, which can also cause hemolytic disease of the newborn.  However, this incompatibility usually has less serious consequences. It occurs when the mother is type O and the baby is A, B, or AB.
As with Rh incompatibility, this means that the mother’s immune system does not recognize the A or B antigens and will see them as foreign substances that trigger an immune response and an attack.
Hemolytic Disease of the Newborn
Hemolytic disease of the newborn, or HDN, is characterized by the destruction of a fetus’s or a newborn’s red blood cells. Rh incompatibility can cause very serious HDN, while ABO incompatibility is usually much less severe. 
When triggered by Rh proteins, this disease can be life-threatening for the baby.
The most common symptom of HDN in a newborn is jaundice in the first 24 hours of life. Jaundice can be severe, especially when caused by Rh incompatibility, and may cause a specific type of brain damage that can lead to cerebral palsy.
Jaundice, Kernicterus, and Cerebral Palsy
Blood incompatibility between a mother and baby can cause various complications, including anemia and jaundice. For ABO incompatibility, the effects are usually mild and go away with time, but with Rh incompatibility, the consequences can be very serious.
A baby can be born with severe jaundice, characterized by a buildup of a substance called bilirubin. This buildup is what causes the characteristic yellowing of the skin and whites of the eyes.
Bilirubin is the product of the breakdown of red blood cells. Normally, the liver processes bilirubin and sends it into the intestines. In a baby with HDN, the liver may not be able to keep up, with the result being a serious buildup of bilirubin and severe jaundice.
The consequences can be serious and include a type of brain damage called kernicterus.
Kernicterus occurs when bilirubin levels are so high that the substance moves into the brain. A baby with severe jaundice may start to act lethargic and may be difficult to rouse, both signs of possible brain damage.
Other signs include floppy muscles interspersed with stiff muscles and arching of the back and neck, a high-pitched cry, a fever, and seizures. Kernicterus is considered a medical emergency. Light therapy is usually used to treat it.
Blue light penetrates the skin and breaks down the bilirubin. Depending on how much damage is caused to the brain by jaundice, this condition may cause cerebral palsy.
Preventing and Treating HDN, Jaundice, and Brain Damage
If a blood type incompatibility is found, preventative measures can be taken to avoid HDN. The mother can be given injections of proteins that prevent her immune system from producing the antibodies that will attack her baby’s red blood cells.
Prevention is always best, but if it is too late and the mother has already produced antibodies against her baby, she needs to be monitored regularly to help keep the baby safe. If the baby is in danger, a doctor can do a blood transfusion to ensure it has enough red blood cells, although this is rarely needed today with good prenatal care.
If the worst happens and a baby is born with severe jaundice, light therapy (phototherapy) is generally used to treat it.  Some babies require a special blood transfusion called an exchange transfusion or a transfusion of intravenous immune globulin.
HDN and the other complications of Rh incompatibility, including cerebral palsy, are highly preventable. With good medical care and screening for blood types, there should be no reason that a baby is put at risk of developing severe jaundice and brain damage.
If your baby has suffered because a blood type incompatibility was not detected and preventative measures were not taken, you can rely on a cerebral palsy lawyer to help you fight for justice.
- Krans, B. (2017, April 18). Blood Typing: Purpose, Procedure & Risks. Healthline.
Retrieved from: https://www.healthline.com/health/blood-typing
- Rh incompatibility: MedlinePlus Medical Encyclopedia. (n.d.). MedlinePlus - Health Information from the National Library of Medicine.
Retrieved from: https://medlineplus.gov/ency/article/001600.htm
- ABO incompatibility: MedlinePlus Medical Encyclopedia. (2020, March 4). MedlinePlus - Health Information from the National Library of Medicine.
Retrieved from: https://medlineplus.gov/ency/article/001306.htm
- Hemolytic Disease of the Newborn (HDN). (n.d.). Stanford Children's Health - Lucile Packard Children's Hospital Stanford.
Retrieved from: https://www.stanfordchildrens.org/en/topic/default?id=hemolytic-disease-of-the-newborn-90-P02368
- Infant jaundice - Diagnosis and treatment. (2020, March 17). Mayo Clinic - Mayo Clinic.
Retrieved from: https://www.mayoclinic.org/diseases-conditions/infant-jaundice/diagnosis-treatment/drc-20373870