When hemolytic disease of the fetus and newborn (HDFN) is a possibility following the birth of a baby, the mother will seek the care of an obstetrician or gynecologist who specializes in the diagnosis and treatment of high-risk pregnancies. Obstetrician/gynecologists in the United States receive their certification from the American College of Obstetricians and Gynecologists (ACOG).
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 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 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.
How do obstetricians provide care to women with high-risk pregnancies?
When an expectant mother has an increased risk for HDFN, obstetricians and gynecologists often will coordinate their care of the pregnant woman with perinatologists. Also known as maternal-fetal medicine specialists, perinatologists are obstetricians/gynecologists with an expertise in managing and treating women with high-risk pregnancies. They undergo two to three additional years of training in the management and treatment of pregnancy-associated genetic, obstetric, medical and surgical complications.
Maternal-fetal medicine specialists become involved in the care of a pregnant woman in whom it is anticipated that a congenital disorder, disease or medical condition may lead to complications during her pregnancy and/or delivery.
When is a pregnant woman at risk of HDFN referred to a perinatologist?
Obstetrician and gynecologists are specialists in female reproductive health, the care and management of women and their fetuses during pregnancy, and the delivery of babies. Expectant mothers are initially screened by obstetricians/gynecologists during the first trimester of their pregnancy. If a pregnant woman’s medical condition or laboratory test results are indicative of an elevated risk for HDFN, she will receive a referral to a maternal-fetal medicine specialistMaternal-fetal medicine specialist An obstetrician who specializes in managing high-risk pregnancies..
Perinatologists offer prenatal (also known as antenatal) consultations, along with direct care, for women who have a preexisting disorder that might be impacted by a pregnancy. After first-trimester screening for clinically significant red blood cell (RBC) antibodies, a woman who is deemed to be at risk for HDFN is referred to a perinatologist, so that she can receive continuous prenatal monitoring and preventive care.
Read more about HDFN signs and symptoms
What tests do maternal-fetal medicine specialists perform?
After a pregnant woman’s first trimester, perinatologists conduct more extensive testing in their patients, such as the serial monitoring of antibody titers and paternal screening for verification of fetal Rhesus (Rh) positivity.
If a critical antibody titer is reached, in which there is a significant risk for fetal hydrops—defined as a buildup of large amounts of fluid in a baby’s tissues and organs that results in swelling—then fetal wellness evaluations are considered mandatory. In such cases, maternal pelvic ultrasonography will be conducted.
Signs of fetal anemia will be monitored with the use of Doppler of the middle cerebral artery (MCA). In situations in which MCA Doppler is not available, amniocentesis may be performed by maternal-fetal medicine specialists. A risk associated with amniocentesis is the potential mixing of RBCs from the mother and the fetus.
Advancements in the care provided by maternal-fetal medicine specialists
Major advancements have been reported in treatment by perinatologists, including intravenous immune globulin (IVIG) therapy, noninvasive fetal genetic testing, and intrauterine transfusions. These improvements have decreased the rates of HDFN and its related fetal/neonatal outcomes.
