In a ceain population, there were 4050 bihs in last one year. There were 50 still bihs. 50 infants died within 7 days where as 150 died within 28 days. What is the neonatal moality rate-

**Core Concept**
Neonatal mortality rate (NMR) is a measure of the number of deaths of infants within the first 28 days of life per 1000 live births. It is an essential indicator of the quality of healthcare provided to newborns and reflects the effectiveness of maternal and child health services.

**Why the Correct Answer is Right**
To calculate the NMR, we need to first determine the number of live births and the number of deaths within the first 28 days. The total number of births is 4050, out of which 50 were stillbirths, leaving 4000 live births. The number of deaths within the first 28 days is 150. The formula for NMR is: (Number of deaths within 28 days / Number of live births) x 1000.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not take into account the number of stillbirths and only considers live births. The correct calculation for NMR requires the total number of births, which includes both live and stillbirths.
**Option B:** This option is incorrect because it uses the total number of births (4050) instead of the number of live births (4000) in the calculation.
**Option C:** This option is incorrect because it calculates the rate using the total number of deaths (200) instead of the number of deaths within the first 28 days (150).
**Option D:** This option is not provided in the question.

**Clinical Pearl / High-Yield Fact**
When calculating NMR, it is essential to distinguish between live and stillbirths, as stillbirths are not considered in the calculation. This is because NMR is a measure of the number of deaths within the first 28 days of life, and stillbirths occur before birth.

**Correct Answer: B. (150 / 4000) x 1000 = 37.5**