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 ⁷
• 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 ⁸ 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