Hydrops fetalis (fetal hydrops) is a serious condition in which a fetus becomes extremely swollen from buildup of fluids in the body tissues. Organs such as the liver and spleen become enlarged, the fetus develops anemia, and the ability of the fetus's blood to carry oxygen is decreased.

Hydrops fetalis can develop for a variety of reasons, such as from problems related to Rh sensitization or chromosomal abnormalities.

Even with treatment, fetal hydrops can cause death of the fetus.