Fetal anemia

Fetal anemia is a characterized by inadequate erythrocytes being delivered to the fetus and can result from many causes.

Pathology

Etiology

• hemolytic disease of the newborn
  • fetomaternal ABO incompatibility
  • fetomaternal rhesus (Rh) incompatibility
• fetal infections
  • fetal parvovirus B19 infection
• haematopoetic abnomalities
  • homozygous alpha thalassemia 
• syndromes
  • Aase syndrome
  • Fanconi anemia
• tumors
  • placental chorioangioma
  • infantile hemangioendothelioma
  • sacrococcygeal teratoma

Radiographic features

Ultrasound

General sonographic features include:

• evidence of fetal hepatomegaly and/or fetal splenomegaly
• effects of subsequent cardiovascular compromise
  • development of hydrops fetalis

Doppler

• increase in fetal middle cerebral arterial (MCA) Doppler time average mean velocity (TAMV): may occur before precipitation of fetal hydrops
• increase in fetal middle cerebral arterial (MCA) Doppler peak systolic velocity (PSV): may occur before precipitation of fetal hydrops
• changes in fetal MCA Doppler are reported to have 88% sensitivity and an 82% specificity for detection of fetal anemias 

Fetal MRI

MRI can be used to detect fetal anemia and some of its sequellae. T1 and T2 relaxation times of relevant areas e.g. the umbilical vein's blood allow for detection.

Treatment and prognosis

Intra-uterine transfusion via the umbilical vein can be successful in selected cases. The overall prognosis will depend on underlying conditions and associations.

See also

• fetal thrombocytopenia