When a fetus suffers from hemolytic disease of the fetus and newborn (HDFN) during pregnancy, the complications can be potentially life-threatening. To delay the onset of 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. and reduce the risk of dangerous complications, intrauterine transfusions (IUTs) are administered to the fetus through the umbilical cord.
Fetal analgesia is used to minimize pain or discomfort for the fetus during the procedure. Limiting fetal distress also helps in keeping the fetus calm and less likely to move, which improves safety and outcomes.
What is HDFN?
Hemolytic disease of the fetus and newborn (HDFN) is an immune-mediated red blood cell 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.
What is an IUTIntrauterine transfusion A procedure that delivers donor red blood cells to the fetus through the umbilical vein to treat severe anemia caused by HDFN.?
When the mother becomes alloimmunized, her immune system develops 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. to her baby’s blood, and they cross the placenta to attack the baby’s red blood cells, progressively destroying them. This leads to fetal anemia, which makes it harder for the blood to carry oxygen around the body. In severe fetal anemia, fetalis hydrops, heart failure or even fetal death can occur.
An IUT is a fetal blood transfusion made up of donor red blood cells. This non-invasive procedure has been shown to help treat fetal anemia, delay or prevent the onset of severe fetal anemia, prevent fetalis hydrops and improve outcomes for the fetus.
Learn more about HDFN treatment and care
The blood transfusion is administered via a needle into the vein of the umbilical cord or via a needle through the mother’s uterus into the fetus’s abdominal cavity.
While an IUT is recommended for the treatment of fetal anemia in HDFN, there are some potential complications related to the procedure. Most complications occur at <20 weeks’ gestation and can be potentially life-threatening.
The use of fetal analgesia during an IUT
The use of fetal analgesia is recommended to reduce the risk of procedure-related complications in IUT, particularly fetal distress.
A fetus cannot feel pain until around 24 weeks’ gestation. The use of a sedative during IUT is therefore recommended in the second half of pregnancy to avoid causing pain and discomfort to the fetus. In some cases, medication to induce fetal paralysis is also used to ensure the fetus does not move during the procedure.
The IUT procedure requires a skilled healthcare professional, as it is a precise and potentially risky intervention. It is essential that the mother and baby remain immobile to avoid any risk of misplacing the needle or puncturing membranes. An ultrasoundUltrasound An imaging test that uses sound waves to monitor fetal growth, development and signs of complications during pregnancy. is taken of the fetus to determine the position of the fetus and to help guide the placement and insertion of the needle. If the fetus is distressed or moves during the procedure, the risks increase.
Often, the mother and baby both receive a sedative to ensure the best outcomes.
