Hydrops fetalis due to isoimmunization

This code signifies a severe form of fetal anemia and generalized edema (hydrops fetalis) specifically caused by an immune response where maternal antibodies attack fetal red blood cells. This typically occurs when there is a blood group incompatibility between the mother and fetus, such as Rh incompatibility. The destruction of fetal red blood cells leads to anemia, heart failure, and fluid accumulation in various fetal compartments.

Assign this code when documentation clearly indicates hydrops fetalis resulting from maternal isoimmunization, often identified through antenatal testing or at birth. This diagnosis is supported by findings such as fetal ascites, pleural effusions, pericardial effusions, skin edema, and placental edema, coupled with evidence of maternal antibodies against fetal red blood cell antigens.

• Ensure documentation specifies "isoimmunization" as the cause of hydrops fetalis; otherwise, a different code for hydrops of unknown etiology may be more appropriate.
• Consider additional codes for the specific type of isoimmunization (e.g., Rh incompatibility) if documented.
• This code is for the fetus affected by the maternal condition, not for the mother's isoimmunization itself.