Neonatal death rates are commonly used to assess neonatal care quality, yet they have limitations, including terminology discrepancies. With improved infection control, over 50% of deaths now occur in the newborn period. Neonatal mortality indicates death within 28 days. Early newborn mortality is within seven days, and late neonatal mortality is between seven and twenty-eight days. Specific neonatal mortality rate by birth weight measures deaths per 1000 live births with the same birth weight. Perinatal mortality combines early neonatal and late fetal mortality.