Rh Negative Pregnant Women and the RhoGAM Shot

"I'm Rh negative an had to get a shot while pregnant, why?"

Rh-negative Mothers and the Importance of Rh Immune Globulin Shots

Rh-negative blood type is a relatively rare blood type, present in only about 15% of the global population. In cases where an Rh-negative mother is pregnant with an Rh-positive baby, there is a risk of Rh incompatibility that can potentially lead to serious health complications for both the mother and the baby.

Rh incompatibility occurs when an Rh-negative mother is exposed to Rh-positive blood from her baby, either during pregnancy or delivery. This exposure can cause the mother's immune system to produce antibodies against the Rh factor, which can potentially lead to hemolytic disease of the fetus and newborn (HDFN) in subsequent pregnancies.

HDFN is a condition where the mother's antibodies attack and destroy the baby's red blood cells, leading to anemia, jaundice, brain damage, and even death in severe cases. To prevent Rh incompatibility and HDFN, Rh-negative mothers are recommended to receive an Rh immune globulin shot, also known as RhIg or RhoGAM, during and after pregnancy.

Rh immune globulin is a blood product that contains antibodies against the Rh factor. When given to an Rh-negative mother, RhIg can prevent her immune system from producing antibodies against the Rh factor, thereby preventing Rh incompatibility and HDN in future pregnancies.

RhIg is typically given to Rh-negative mothers at around 28 weeks of pregnancy, and again within 72 hours after delivery if the baby is Rh-positive. RhIg may also be given after any procedure that may cause mixing of maternal and fetal blood, such as amniocentesis or miscarriage.

While RhIg is generally safe and effective, like any medication, it may cause side effects in some individuals, such as pain or swelling at the injection site, fever, or allergic reactions. It is important for Rh-negative mothers to discuss the risks and benefits of RhIg with their healthcare provider and to report any side effects or adverse reactions.

Anti-D Antibody Titers

If a mother has Anti-D antibodies, it means that she has been previously sensitized to the Rh factor (D antigen), either through a previous pregnancy, blood transfusion, or other exposure to Rh-positive blood. This can potentially lead to hemolytic disease of the fetus and newborn (HDFN) in future pregnancies.

To monitor the risk of HDFN and the severity of the mother's Anti-D antibodies, healthcare providers typically perform antibody titers during pregnancy. Antibody titers are blood tests that measure the concentration and potency of the mother's Anti-D antibodies.

The results of antibody titers can help healthcare providers to determine the risk of HDN and the appropriate course of treatment. For example, if the mother's antibody titers are low, it may indicate a lower risk of HDN and close monitoring may be sufficient. If the mother's antibody titers are high, it may indicate a higher risk of HDN, and additional interventions, such as early delivery or intrauterine blood transfusions or even exchange transfusions after deliver, may be necessary.

In addition to monitoring the mother's antibody titers, healthcare providers may also monitor the baby's well-being through regular ultrasounds, amniocentesis, or other diagnostic tests to detect any signs of anemia, hydrops, or other complications.

Intrauterine Transfusions for HDFN

Intrauterine transfusion (IUT) is a medical procedure in which blood is transfused directly into the fetal bloodstream while the fetus is still in the uterus. This procedure is typically performed to treat severe cases of hemolytic disease of the fetus and newborn (HDFN) caused by Rh incompatibility between the mother and fetus.

During IUT, a needle is inserted into the fetus's abdomen or umbilical cord under ultrasound guidance, and blood is transfused through the needle into the fetal circulation. The blood used for the transfusion is typically Rh-negative and free of any antibodies that could further exacerbate the HDFN.

IUT is typically performed when the fetus is between 18 and 34 weeks gestation, depending on the severity of the HDFN and the availability of specialized medical facilities. The procedure is typically performed in a specialized center by a team of experienced healthcare providers, including maternal-fetal medicine specialists, neonatologists, and transfusion medicine specialists.

IUT carries some risks, including infection, bleeding, and premature labor. However, when performed by experienced healthcare providers, the risk of complications is relatively low, and the benefits of preventing severe HDFN and its associated complications may outweigh the risks.

Exchange Transfusion for HDFN

An exchange transfusion is a medical procedure that may be used to treat severe cases of hemolytic disease of the fetus and newborn (HDFN) caused by Rh incompatibility between the mother and fetus. During this procedure, a newborn's blood is gradually replaced with Rh-negative donor blood in order to remove the Rh-positive red blood cells that have been attacked by the mother's antibodies.

The procedure involves placing catheters into the baby's umbilical vessels or other blood vessels, and gradually removing small amounts of the baby's blood and replacing it with donor blood.

The goal of the exchange transfusion is to reduce the levels of bilirubin, a yellow pigment that can build up in the baby's blood and cause jaundice, as well as to remove the Rh-positive red blood cells that have been attacked by the mother's antibodies.

Exchange transfusion may be necessary when the baby's bilirubin levels are very high, or when the baby is showing signs of severe anemia, such as low oxygen levels, fast heartbeat, or lethargy. The procedure can help to prevent or treat the complications associated with severe HDN, such as brain damage or organ failure.

Kleihauer-Betke Test

The Kleihauer-Betke (KB) test is a laboratory test used to quantify the amount of fetal-maternal hemorrhage (FMH) that has occurred in a pregnant woman. FMH is the mixing of fetal and maternal blood that can occur during pregnancy, childbirth, or after an invasive procedure, or trauma.

The KB test involves staining a maternal blood sample with a special stain, which specifically stains fetal red blood cells. The stained cells are then examined under a microscope to determine the percentage of fetal cells in the maternal blood sample. The results of the KB test can help determine the appropriate dose of Rh immune globulin (RhIg) that an Rh-negative mother should receive after a potentially sensitizing event, such as childbirth or miscarriage.

The KB test is especially important for Rh-negative mothers because if a significant amount of fetal blood enters the maternal circulation, it can trigger the production of antibodies against the Rh factor. This can cause hemolytic disease of the fetus and newborn (HDFN) in future pregnancies if the next baby is Rh-positive. 

This test is often proceeded by a "Fetal Bleed Screen" which is a more rapid test to determine if mom and baby's blood have mixed. The Fetal Bleed Screen looks for the presence of RhD positive red blood cells within the blood of the Rh negative mother. This test is read microscopically to determine whether it is positive or negative. If positive, a Kleihauer-Betke test is performed to determine if the standard dose of ONE vial of RhIG will cover the bleed, or if more vials are necessary. One vial of RhIG can protect against 30mL of RhD whole blood.