Transplacental medical therapy is performed by giving the mother medicine that in turn passes to the fetus by crossing the placenta. The most common transplacental treatment in obstetrics is maternal steroids administration to promote fetal organ maturation in cases of threatening premature birth.
Certain biochemical and endocrine fetal disorders can be treated by transplacental therapy. Transplacental medical therapy can also be utilized to treat life threatening fetal cardiac arrhythmias using antiarrhythmic agents such as digoxin or flecainide. This treatment poses some risks to the mother, and should be done in close collaboration with a cardiologist. Another example of a fetal treatment via the transplacental route is maternal administration of intravenous immunoglobulin and steroids for pregnancies complicated by alloimmune thrombocytopenia.