If the delivery has been planned then antigen negative platelets should be available in case the infants platelet count is low on a cord blood sample. After birth
The most rapidly effective treatment in infants with severe hemorrhage and/or a very low platelet count (<30,000  μL−1) is the transfusion of compatible platelets (i.e. platelets from a donor who, like the mother, lacks the causative antigen). If  antigen negative platelets are unavailable, then standard neonatal platelet transfusions should be given until antigen negative platelets become available. If a platelet transfusion is not available immediately then the infant can be given IVIG (1g/kg) however, this will have no effect on the platelet count before 24 to 72 hours.A platelet transfusion is required immediately if there is severe or life-threatening bleeding. If life-threatening bleeding occurs, for example an intracranial hemorrhage, then the platelet count needs to be increased to decrease the risk of further bleeding (> 100,000  μL−1).Any infant with suspected NAIT should have an ultrasound of the head within the first 24 hours after birth to make sure that there is no evidence of an intracranial hemorrhage.If the infant has a platelet count >30,000  μL−1 and no evidence of bleeding, then the baby can be monitored with blood counts until the blood counts return to normal, without the need for any additional treatment. In the past, infusions of IVIG (1 g/kg/day for two days) have been given to the infant and have been shown to rapidly increase the platelet count.
Other conditions causing a low platelet count
Other conditions that can cause a low platelet count in the neonate include bacterial and viral infection, disseminated intravascular coagulation and other rare congenital conditions associated with a low platelet count. Pathophysiology
Platelets have many proteins on their surface. Each person has a different set of proteins, which are inherited from their parents. These different platelet proteins make different platelet groups, just like different proteins on red blood cells make different blood groups. These differences do not affect how the platelets work. However, if a baby inherits a protein that is found on the fathers platelets but is absent from the mothers platelets, the mother may respond to this foreign protein by developing an antibody that fights against it.This antibody may pass from the mothers blood into the babys blood and attach to the babys platelets. This antibody destroys the babys platelets and suppresses production of fetal platelets, they are also thought to weaken the blood vessel walls (vascular integrity) and affect production of new blood vessels (angiogenesis). This results in an increased risk of bleeding for the baby, and this can lead to the babys death. The mothers antibodies can remain in the babys bloodstream for weeks, and bleeding can occur in the baby before birth (fetal), during birth or after birth (neonatal).A number of different proteins can cause NAIT, about 80% of cases are caused by antibodies against platelet antigen HPA-1a, 15% by anti-HPA-5b, and 5% by other antibodies (e.g. HPA-1b, HPA-15, HPA-3 and HPA-9b).