Pregnancy presents a vast array of symptoms, conditions and potential health problems. While most problems have indicators such as physical signs and symptoms, a person’s blood type can create problems which cannot be physically felt. Rhesus (Rh) is the measure for the four major blood types: A, B, AB, or O. The types of antigens on the blood cells determines the blood type. The Rh factor is a specific type of a protein which is located on the surface of red blood cells; D antigen. The Rh factor is either positive or negative. When a couple decides to have a child, their blood types will determine if there is a potential problem. A mother who is Rh-negative with a father who is Rh-positive can create a problem should the fetus inherit the Rh factor from the father. If the fetus and the mother have differing Rh factors and any of the baby’s blood mixes with the mother’s blood, it can trigger the mother’s body to produce antibodies, cross the placenta and literally attack the baby’s blood.

Women without the Rh D antigen are Rh-negative and can become sensitized or maternal alloimmunization, during pregnancy or following the birth if the baby is Rh-positive. They will begin to produce antibodies against the Rh-positive baby. Once the Rh protein enters a Rh-negative mother’s bloodstream it is recognized as foreign and her body reacts to protect her immune system and creates antibodies to clear her system; leaving a record of this in order to protect her in the future (Wickham, 2005).  This occurs in the same way a person’s body would react to any infection. This may or may not affect the current pregnancy; however, production of antibodies can cause hemolytic disease of the fetus and newborn in subsequent pregnancies (Dixon, 2008).  A fetus affected by a hemolytic disease will secrete abnormally high levels of bilirubin directly into the amniotic fluid.  There are several ways sensitization can occur such as in the event of a miscarriage, an ectopic pregnancy or a blood transfusion. Chorionic villus sampling or an induced abortion can also create this problem.

The Rh D antigen was first discovered in the 1950s when about one out of every two Rh-negative women became sensitized to the antigen and lost her baby (Cerrato, 2006). As this problem began to gain notoriety and studies began to determine ways to prevent this problem, the morality rates dropped drastically. By 1986 studies such as amniocentesis, amniotic fluid analysis, and intrauterine transfusions were being practiced and the odds of the child surviving in this situation had vastly improved (Cerrato, 2008).  Detecting the problem during pregnancy is the key to proactively monitoring and attempting to keep both the mother and fetus safe.

There are more than 100 antigen varieties on red blood cells and the RhD is the most common with the RhD positive being dominant. RhD-negative status varies among the different ethnic groups: in white, 15% are RhD-negative; in African American, 5% to 8% are RhD negative; and in Asians and Native Americans, 1% to 2% are RhD-negative (Hensley, Coughlin, & Klein, 2009). The chance of susceptibility varies among women. Some will become sensitive with only a small amount of blood while others will need a greater quantity to produce the sensitization. Sensitization, also called alloimmunization, can occur during the third trimester and during birth, following miscarriage, termination, antepartum hemorrhage or abdominal trauma (Dixon, 2008).  An RhD immunoglobulin has been identified which can be given to an Rh-negative mother during pregnancy for prophylactic treatment which has shown to be effective in reducing the risk.

Nursing Process

Analysis with cell-free DNA testing of the Rh-negative mother is one test which is thought to be beneficial in preventing sensitization. This test starts with a maternal blood sample subjected to DNA amplification and gel electrophoresis to pinpoint the presence of the specific DNA sequence for the RhD protein (Cerrato, 2006). DNA is taken out and heated to be able to determine the DNA chains. After cooling it is reheated in the presence of a polymerase, triggering the synthesis of additional copies of each strand (Cerrato, 2006). This creates a pattern which indicates the presence of a DNA fingerprint identifying the antigen. The negative side of this test is there have been false-positive results; however, accuracy to 99.1% has been demonstrated.