Neonatal Alloimmune Thrombocytopenia is a disease that affects fetuses and newborns. Genetic differences between the fetus and mother may result in the expression of certain antigens by fetal platelets, not expressed by the mother. Fetomaternal transfusions result in the recognition of these antigens by the mother’s immune system as non-self, with the subsequence generation of allo-reactive antibodies which cross the placenta. NAIT, hence, is caused by transplacental passage of maternal platelet-specific alloantibody and rarely human leukocyte antigen (HLA) allo-antibodies (which are expressed by platelets) to fetuses whose platelets express the corresponding antigens.