Birthrates refer to the number of live births per thousand of the population in a particular period. Synonyms for birthrates include fertility rates, natality rates, and birth frequencies. Fertility rates refer to the average number of children born to a woman during her reproductive years. Natality rates are similar to birthrates but also include the number of stillbirths and infant deaths. Birth frequencies refer to the overall number of births per year or other time frame. All these terms are used in demographic studies and policy-making, as birthrates have a significant impact on a country's population growth, social structure, and economic development.