A district epidemiologist in Uttar Pradesh is analyzing health statistics for a population of 500,000. In the past year, there were 25,000 live births. Of these, 750 infants died before reaching 1 year of age. Additionally, 125 women died from pregnancy-related causes during pregnancy or within 42 days of termination of pregnancy. The total number of deaths in the population was 5,000. Calculate the Infant Mortality Rate (IMR) and Maternal Mortality Ratio (MMR) for this district, and identify which indicator is more sensitive to short-term changes in maternal healthcare quality.