**Question:** Causes of antepartum hemorrhage are all except

A. Placenta previa
B. Placental abruption
C. Bleeding disorder
D. Vasa praevia

**Core Concept:** Antepartum hemorrhage (APH) is a significant medical emergency in obstetrics, referring to bleeding during pregnancy, particularly during the third trimester and labor. The correct answer focuses on excluding certain causes that are not antepartum hemorrhage.

**Why the Correct Answer is Right:**

Option C (Bleeding disorder) is not a specific cause of antepartum hemorrhage but rather a broad category that could potentially lead to hemorrhage. APH should be distinguished from other types of bleeding disorders, such as hemophilia or von Willebrand disease, which have distinct clinical presentations and management strategies.

Option D (Vasa praevia) is a rare and specific condition where part of the fetus's blood vessels protrude through the lower segment of the uterus. Vasa praevia can lead to antepartum hemorrhage, but excluding it from the correct answer ensures that we discuss typical causes of APH.

Option A (Placenta previa) is a condition where the placenta partially or completely covers the cervix, increasing the risk of antepartum hemorrhage. It is essential to understand placenta previa to differentiate it from other causes of APH.

Option B (Placental abruption) is a condition where the placenta detaches prematurely from the uterine wall, potentially causing antepartum hemorrhage. This answer focuses on excluding unrelated causes rather than discussing placental abruption itself.

**Why Each Wrong Option is Incorrect:**

Option C (Bleeding disorder) is incorrect because it is a broad category and not a specific cause of antepartum hemorrhage.

Option D (Vasa praevia) is incorrect because it is a rare condition and should not be excluded from the correct answer.

Option A (Placenta previa) is incorrect because it is a potential cause of antepartum hemorrhage, making it relevant to the question.

Option B (Placental abruption) is incorrect because it is a specific cause of antepartum hemorrhage, not a cause to be excluded.

**Clinical Pearl:** Understanding the various causes of antepartum hemorrhage, such as placenta previa and placental abruption, is crucial for accurately diagnosing and managing obstetric emergencies. It is essential to know the difference between antepartum hemorrhage and hemorrhage from other conditions like vasa praevia or vasa praevia and abruptio placentae.