Most frequent cause of neonatal thrombocytopenic purura is –
**Core Concept**
Neonatal thrombocytopenic purpura refers to a condition characterized by low platelet count in newborns, often leading to bleeding manifestations. This condition can result from various causes, including maternal and neonatal factors.
**Why the Correct Answer is Right**
The most common cause of neonatal thrombocytopenic purpura is maternal alloimmune thrombocytopenia. This condition occurs when the mother has anti-platelet antibodies, which can be inherited or acquired, and these antibodies cross the placenta, attacking the fetal platelets. This leads to a decrease in platelet count in the fetus, resulting in thrombocytopenic purpura. The antibodies typically target specific platelet antigens, such as HPA-1a.
**Why Each Wrong Option is Incorrect**
* **Option A:** While maternal infections, such as rubella or CMV, can cause neonatal thrombocytopenia, they are less common causes compared to maternal alloimmune thrombocytopenia.
* **Option B:** Fetal alloimmune thrombocytopenia, caused by the mother's immune response to fetal platelets, is a rare condition and not the most frequent cause.
* **Option C:** Neonatal sepsis can cause thrombocytopenia, but it is usually associated with other signs of infection and not the most common cause of isolated thrombocytopenic purpura.
**Clinical Pearl / High-Yield Fact**
Maternal alloimmune thrombocytopenia is the leading cause of neonatal thrombocytopenic purpura, and identifying this condition is crucial for timely management and prevention of bleeding complications in newborns.
**Correct Answer:** D. Maternal alloimmune thrombocytopenia.