Pregnant women may develop antibodies in response to antigens on fetal red blood cells. The antibodies that result can cross the placenta to the fetus and break down red blood cells, leading to fetal anaemia. This has become less common with the routine use of anti D immunoglobulin in pregnant women with a Rhesus D-negative blood group and no pre-existing anti-D antibodies, but remains a cause of fetal death. Currently, standard management involves monitoring antibody titres in conjunction with ultrasound assessment of fetal well-being, and the use of intrauterine transfusion when fetal anaemia is diagnosed. Unfortunately, intrauterine transfusion poses significant risks because of its inherent invasiveness and procedure-related risks, including a risk of perinatal death.

Intravenous immunoglobulin has been proposed as an alternative form of treatment, with the advantage of being less invasive. There are no randomized trials of intravenous immunoglobulin given antenatally to women with severe fetal red blood cell alloimmunization to show if this offers any benefit over other forms of treatment or no treatment, but there are case series suggesting a possible role in delaying the onset of fetal anaemia requiring invasive intrauterine transfusion.