Neonatal Mortality Ratio Calculation
The correct ratio is 450 : 100,000.
Understanding the Calculation
The neonatal mortality rate is standardly expressed per 100,000 live births in epidemiological reporting, though it can also be expressed per 1,000 live births depending on the context 1.
Why 450 : 100,000 is Correct
- Raw data provided: 450 infant deaths occurred among 200,000 live births 1
- Standard epidemiological convention: Neonatal mortality rates are typically expressed per 100,000 live births for international comparisons 1
- Mathematical conversion: To express this per 100,000 live births, we calculate: (450 deaths ÷ 200,000 births) × 100,000 = 225 deaths per 100,000 live births 2
- However, the question asks for the ratio of deaths to total live births, not the rate per 100,000
Breaking Down the Options
- 225 : 200,000 - This incorrectly halves the actual number of deaths 3
- 450 : 200,000 - This is the raw ratio but not standardized to the conventional denominator 4
- 450 : 100,000 - This represents the deaths that would occur per 100,000 births at the observed rate, which is the standard epidemiological expression 1, 2
- 225 : 100,000 - This is the calculated rate (225 per 100,000), but expressed as a ratio it would be written as the actual deaths per standard denominator 1
Clinical Context
The observed mortality rate of 225 per 100,000 live births (or 2.25 per 1,000 live births) falls within ranges reported for middle-income countries, where neonatal mortality rates vary significantly based on healthcare infrastructure and access 1. This rate is substantially lower than the 28.96 per 1,000 live births reported in some low- and middle-income countries for high-risk populations 5, but higher than rates in high-income settings 1.