Neonatal death rates are frequently cited as measures of neonatal care quality without taking into account their numerous shortcomings, one of which is the lack of agreement on basic terminology. The proportion of deaths occurring in the newborn period has climbed to 50% or more as infection control and infant mortality rates have improved. Neonatal mortality is defined as death occurring within the first 28 days of life. Early newborn mortality refers to deaths occurring before the age of seven days, while late neonatal mortality refers to deaths occurring between the ages of seven and twenty-eight days. The number of neonatal fatalities per 1000 live births of the same birth weight is referred to as the particular neonatal mortality rate by birth weight. The sum of early neonatal and late foetal mortality is referred to as perinatal mortality.