**Core Concept:** Postnatal maternal mortality is a critical issue in global public health, particularly in low-resource settings. It represents the number of deaths per 100,000 live births within 42 days of childbirth. Several factors contribute to maternal mortality, including direct and indirect causes. Direct causes refer to complications arising from pregnancy, childbirth, or the postpartum period, while indirect causes involve underlying health conditions that worsen during pregnancy or childbirth.

**Why the Correct Answer is Right:** In this question, we are focusing on direct causes of maternal mortality. The correct answer, **C. Preeclampsia and eclampsia**, are hypertensive disorders characterized by significant proteinuria and neurological manifestations. These conditions develop during pregnancy or the postpartum period and can lead to severe complications, including stroke, pulmonary edema, and renal failure. Preeclampsia and eclampsia can result in maternal death if not promptly diagnosed and treated.

**Why Each Wrong Option is Incorrect:**

A. **Puerperal sepsis (Option A)** refers to infections during childbirth, which is an indirect cause of maternal mortality and not the primary direct cause.
B. **Hemorrhage (Option B)** is a direct cause of maternal mortality, but preeclampsia and eclampsia (Option C) are more specific direct causes.
D. **Perinatal asphyxia (Option D)** is a condition affecting the newborn, not a direct cause of maternal mortality.

**Clinical Pearl:** Understanding the direct causes of maternal mortality helps healthcare providers prioritize their interventions to reduce maternal mortality rates. Early recognition and management of preeclampsia and eclampsia are crucial for maternal survival, emphasizing the importance of a thorough prenatal and postnatal examination and monitoring.