A pregnancy affected by hemolytic disease of the fetus and newborn (HDFN) may progress uneventfully without the need for intervention or treatment in utero.
However, in the first trimester and up to 20 weeks of gestation, when pregnant women have very aggressive antibodiesAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens. or there are other complications, intravenous immunoglobulinIntravenous immunoglobulin A therapy made from donated antibodies that may help reduce the mother’s immune response and protect the fetus. (IVIGIntravenous immunoglobulin A therapy made from donated antibodies that may help reduce the mother’s immune response and protect the fetus.) and plasmapheresis may be recommended to delay or potentially prevent fetal anemiaAnemia A condition that occurs when the body doesn’t have enough healthy red blood cells to carry oxygen to its tissues. In HDFN, anemia occurs when maternal antibodies destroy fetal red blood cells..
What is HDFN?
Hemolytic disease of the fetus and newborn (HDFN) is an immune-mediated red blood cell (RBC) disorder that occurs when a baby’s RBCs break down quickly, which is called hemolysis. HDFN is caused by a mismatch between a mother’s and her baby’s blood type (A, B, AB, or O) or Rhesus (RhRh factor A protein or antigen found on red blood cells. When an Rh-negative mother carries an Rh-positive fetus, her immune system may make antibodies that attack the fetus' red blood cells.) factor (Rh-positiveRh-Positive A blood type trait that means your red blood cells have the Rh(D) antigen. or Rh-negativeRh-Negative A blood type trait that means your red blood cells lack the Rh(D) antigen.) during pregnancy. Numerous antibodies to RBC antigensAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens. can be linked to HDFN, such as those from the ABO and Rh blood groupBlood group A classification of blood based on inherited markers found on red blood cells. The ABO and Rh blood groups are most common in HDFN. systems.
What is plasmapheresis?
Plasmapheresis, also known as plasma exchange, is used to treat a variety of conditions, including autoimmune diseases, blood toxins, neurological diseases and high levels of cholesterol. In HDFN-affected pregnancies, it involves extracting the mother’s blood and separating the plasma, which includes the antibodies that cause HDFN, from the blood cells, temporarily replacing it with saline or albumin while the plasma is cleansed in an apheresis machine.
The clean plasma is then put back into the body. This reduces the antibodies in the mother’s blood, stopping them from attacking the fetus’ red blood cells and helping to guard against the onset of fetal anemia.
Plasmapheresis is a temporary treatment, as the antibodies can be reproduced by the mother’s immune response to the fetus’ blood. There is no fixed protocol on the frequency of plasmapheresis, with several plasmapheresis treatments generally required, depending on the levels of antibodies in the mother’s blood. In more high-risk cases, it can be combined with IVIG.
Learn more about HDFN treatment and care
Benefits of plasmapheresis
In the first trimester and up to 20 weeks, pregnancies affected by HDFN —particularly in subsequent pregnancies following HDFN-related loss—can benefit from plasmapheresis by delaying the onset of fetal anemia and potentially delaying or avoiding the need for intrauterine transfusionIntrauterine transfusion A procedure that delivers donor red blood cells to the fetus through the umbilical vein to treat severe anemia caused by HDFN. (IUTIntrauterine transfusion A procedure that delivers donor red blood cells to the fetus through the umbilical vein to treat severe anemia caused by HDFN.). It can also help improve outcomes for the fetus.
Complications of plasmapheresis
The plasmapheresis procedure during pregnancy is considered generally safe for the mother and baby. However, side effects may occur for the mother, including dizziness, blurry vision, a drop in blood pressure, fatigue, stomach cramps, a cold feeling, an allergic reaction, bruising or a blood clot. These side effects are temporary, and their severity and duration vary from person to person.
Plasmapheresis and IVIG
The combination of plasmapheresis and IVIG is recommended in cases where the risk is high for the HDFN-affected fetus. This combined treatment method has been shown to reduce antibody titers, delay IUT and help avoid fetal death.
