Infant mortality rate refers to the number of deaths of children under one year per 1,000 live births, serving as a key indicator of public health and societal conditions. Historically, scholars such as Sigmund Engel highlighted significant statistical variations in Europe, noting 100–300 deaths per 1,000 infants annually, while Margaret Sanger associated high fertility rates with increased mortality due to poverty and unhygienic conditions.
Others, like the United States Department of State, emphasized gender differences in rural China, where girls experienced greater mortality risks. Jimmy Carter recognized progress in the U.S. but pointed out remaining challenges, and Halliday Sutherland challenged assumptions regarding the effects of contraception. These diverse viewpoints together illustrate how socioeconomic factors, access to healthcare, and demographic patterns influence infant survival rates worldwide.