Hydrops Fetalis

What is hydrops fetalis?

Hydrops fetalis—or hydrops—is a condition in which large amounts of fluid build up in a baby’s tissues and organs, causing extensive swelling (edema). Hydrops fetalis is sometimes used as a synonym for homozygous alpha thalassemia, a lethal or life-threatening disease of mid and late fetal development caused by the inability to make red blood cells. The condition, which can be diagnosed before or after birth, is relatively rare in the United States due to advances in the prevention of hemolytic diseases of the unborn. It can, however, be life-threatening. Nearly half of the babies born with hydrops do not survive.

There are two types of hydrops:

  • Immune hydrops fetalis, which occurs when the mother’s immune system causes a baby’s red blood cells to breakdown; this is the most dangerous complication of hemolytic disease of the newborn.
  • Non-immune hydrops fetalis, which occurs when disease or other complications interfere with a baby’s ability to manage fluid; this is the most common type of hydrops. Alpha thalassemia major (four gene alpha thalassemia, or homozygous alpha thalassemia) interferes with the fetus’ ability to make red blood cells.

How we care for hydrops fetalis

Our Thalassemia Program cares for children with hydrops fetalis. We are one of only six programs designated as centers of excellence in thalassemia by the National Cooley’s Anemia Foundation and one of only seven centers sponsored by the federal Centers for Disease Control and Prevention for the prevention of thalassemia complications.