fertilitetsrater

Fertilitetsrater, or fertility rates, are demographic indicators that describe the level of childbearing in a population. The term covers several measures, most notably the total fertility rate (TFR) and the age-specific fertility rates (ASFR).

The total fertility rate is the average number of children a woman would have over her reproductive lifetime if current age-specific fertility rates persisted. It is calculated by summing the ASFR across the standard reproductive ages (commonly 15–49) and multiplying by the width of the age interval, usually five years. The result is expressed as children per woman. ASFRs describe the number of births to women in a specific age group per 1,000 women of that age in a given year. By contrast, the crude birth rate measures births per 1,000 people in the whole population per year, and is influenced by the age structure of the population.

A TFR around 2.1 children per woman is often viewed as the replacement level in many developed countries; rates below this level, if sustained, tend to be associated with an aging population and potential long-term population decline, while higher rates can contribute to growth. Fertility patterns vary widely between regions and over time due to factors such as education, female labor force participation, access to contraception, housing costs, childcare availability, cultural norms, and government policies.

Fertilitetsrater are used for planning in health, education, housing, and pensions, and are subject to revisions as new data become available. They are one part of broader demographic measures that inform population projections and policy discussions.