**Question:** In a certain population, there were 4050 births in the last one year. There were 50 still-births. 50 infants died within 7 days whereas 150 died within the first 28 days. What is the neonatal mortality rate?

**Core Concept:** Neonatal mortality rate is the number of neonatal deaths divided by the number of live births, multiplied by 1000.

**Why the Correct Answer is Right:**

The neonatal mortality rate (NMR) is calculated using the formula:

NMR = [(Number of neonatal deaths / Total number of live births) x 1000]

In this scenario, there were 50 stillbirths and 200 (50 + 150) neonatal deaths (within 7 days and 28 days). The number of live births is 4050 (total births minus stillbirths).

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because the calculation does not match the correct formula for determining NMR.
B. Similar to option A, this choice does not use the correct formula for calculating NMR.
C. This option is incorrect because it only considers deaths within the first 7 days, which is not the standard definition of neonatal mortality.
D. This option is wrong as it does not use the correct NMR formula and does not account for stillbirths.

**Why the Correct Answer is Right (Explanation):**

The correct answer (D) uses the correct NMR formula and considers both live births and neonatal deaths (within 7 days and 28 days).

**Clinical Pearl:**

The neonatal mortality rate is a crucial metric for evaluating healthcare systems' effectiveness in providing care to newborns. A lower NMR indicates better neonatal care and higher NMR indicates a need for improvement in newborn care.

**Correct Answer:**

**Correct Answer: D**

Neonatal mortality rate (NMR) = [(200 / 4050) x 1000] = (0.05) x 1000 ≈ 5%

So, the neonatal mortality rate in this population is approximately 5%.