By on January 5, 2018

Understanding Fetal Anemia

The following blog is a summary of the Fetal Anemia Patient Handout, created by the Society for Maternal-Fetal Medicine with the help of Stephen Bacak, DO, MPH and T. Flint Porter, MD.

What is Fetal Anemia?

Fetal Anemia can occur when a fetus’ red blood cell count decreases prior to delivery. Red blood cells are vital for the transportation of oxygen throughout the body and if the red blood cell count is too low then the baby not be able to get the amount of oxygen it needs. While severe fetal anemia is rare, it can be dangerous to the health of the developing baby.

How Does Fetal Anemia Develop?

There are several causes or conditions that can contribute to fetal anemia. These causes can vary from a conflict between the mother and fetus’ RBC’s, infections, genetic or metabolic syndromes.

  • Maternal RBC alloimmunization – This happens as a result of the mother and the fetus’ red blood cells are not compatible, causing the mother’s cells to attack the fetus’ cells by producing antibodies.
  • Parvovirus infection/fifth disease – This infection/disease is a common childhood illness that can cause a rash on the face and body. If left untreated, the virus can begin to attack a fetus’ bone marrow.
  • Genetic and metabolic disorders – Disorders that may experience fetal anemia include down syndrome, Niemann-Pick disease, Gaucher disease, Fanconi anemia, G-6-PD deficiency and alpha-thalassemia. In addition to genetic and metabolic disorders, some twin pregnancies may experience this as well due to the sharing of the placenta.

How is Fetal Anemia Managed?

The first step to managing fetal anemia is figuring out the blood type of the father. According to the Society for Maternal Fetal Medicine, This allows your doctor to determine if there is a risk for fetal anemia depending on the potential blood type of the baby. If it is not possible to find the blood type of the father, amniocentesis or cell-free DNA testing of the mother’s blood can be used to determine the baby’s blood type. In the event that fetal anemia occurs, the fetus could experience heart issues or fluid buildup making it important to do early testing.


Maternal Fetal Medicine blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!