Know All About
RH GROUP & RH INCOMPATIBILITY
Definition:
Like major blood groups A, B, AB & O there is another group called the Rh group. This is an antigen found on the surface of the Red Blood Cells. Most people are Rh +ve, i.e. their RBCs have Rh antigen on their surface. Those who do not have this Rh antigen on the surface are called Rh –ve. In 1940, Landsteiner & Alexander S Wiener discovered this antigen on the surface of RBCs. (ABO system of blood group were discovered 1900 by Landsteiner) It is called the Rh antigen as it is found in Rhesus species of monkeys.
Why is Rh factor so important?
If Rh +ve RBCs get into the blood of Rh –ve patients, they start producing antibodies against Rh factor. By the time antibodies are formed, blood is so much diluted that no harm occurs. Harmful reactions may occur when this Rh –ve patient is again exposed to Rh +ve blood. It may also result in Death.
Signs & Symptons
Signs in a newborn:
- Paleness.
- Jaundice (yellow skin and eyes) that begins within 24 hours after delivery.
- Unexplained bruising or blood spots under the skin.
- Tissue swelling (edema).
- Breathing difficulty.
- Seizures.
- Lack of normal movement.
- Poor reflex response.
Causes
Infection with the herpes zoster virus. Incubation period after exposure is 7 to 21 days.
A newborn is protected for several months from chickenpox if the mother had the disease prior to or during pregnancy. The immunity diminishes in 10 to 12 months.
Risk Increases With
- Each pregnancy after the first involving different blood types.
- Previous blood transfusions. These might have contained unidentified, incompatible blood types.
Prevention
- An Rh –ve mother has to be prevented from forming Anti-Rh antibodies and these dreaded complications would not occur.
- A simple blood test can tell about a woman’s Blood group and Rh status. Another blood test called an antibody screen can show if an Rh –ve woman has formed antibodies.
- Obtain prenatal care throughout pregnancy. Medical supervision early in pregnancy is essential to determine the risk of Rh incompatibility.
- Special anti-Rh gamma globulin is given to the mother at 28 weeks gestation and within 72 hours after delivery, miscarriage, ectopic pregnancy or abortion. This prevents formation of antibodies that might affect future infants.
Diagnostic Measures
- Medical history and physical exam by a doctor. Tell your doctor if you have had a miscarriage or abortion.
- Blood tests to: type mother’s, father’s and infant’s blood; measure the mother’s Rh-positive antibodies; and detect hemolytic anemia in the infant’s blood.
- Amniocentesis.
Possible Complications
- Permanent neurological damage, such as cerebral palsy or hearing loss (rare).
- Blood-transfusion reaction.
Probable Outcomes
With prompt recognition of the disorder, damage to the infant can be prevented with exchange transfusions.
TREATMENT
If you have an Rh-negative blood type:
- Tell any doctor. Make sure this information is in ALL your medical records.
- Rh Immunoglobulin (RhIg) is a blood product that can prevent sensitization of an Rh –ve mother. It suppresses her ability to react to Rh +ve RBCs. RhIg is safe and easily available. With its use sensitization can be prevented almost all the time. RhIg is NOT useful if mother already has antibodies.
Is Rhlg safe?
Yes RhIg is safe for use in pregnancy. Only known side effects are soreness at the site of the injection.
When is RhIg used?
- During pregnancy & after delivery – If the woman with Rh –ve blood has not formed antibodies, she may be given RhIg around 28th week. Of pregnancy. This will take care of the small number of patients who develop antibodies in last trimester of pregnancy. Shortly after delivery if child is Rh +ve mother should be injected with RhIg.
- After an abortion.
- After post-partum sterilization as she may decide to have a pregnancy or sterilization may fail.
Contact your Doctor
Your baby has any of the following after returning home from hospital:
- Fever.
- Jaundice.
- Poor appetite or poor weight gain.
- Excessive crying that does not stop when the baby is held.