What is the most common cause of neonatal thrombocytopenia?

The most common cause of neonatal thrombocytopenia is maternal alloimmunization. This condition occurs when a mother develops antibodies against fetal platelet antigens that she does not possess. These antibodies can cross the placenta, leading to the destruction of the fetal platelets and subsequently resulting in thrombocytopenia in the newborn.

Neonatal thrombocytopenia can manifest in various ways, including an increased risk of bleeding and bruising in the infant. Understanding maternal alloimmunization is crucial for obstetricians because it highlights the importance of identifying potential immune-mediated causes of low platelet counts in neonates. The condition is influenced by factors such as blood group incompatibility, particularly involving HPA (Human Platelet Antigen) systems.

Maternal conditions like preeclampsia can also lead to thrombocytopenia in the neonate due to placental insufficiency and other factors; however, they are not the predominant cause. Platelet transfusion reactions and maternally inherited platelet antigen disorders are less common and do not constitute the primary source of neonatal thrombocytopenia, making them less relevant in this context.

Recognizing maternal alloimmunization as a leading cause of neonatal thrombocytopenia allows healthcare providers to effectively monitor and manage