The birth rate is the ratio between the number of live-born births in the year and the average total population of that year.

With a negative relationship, population growth is limited at low densities and becomes less limited as it grows. This in turn led to a decrease in per capita birth rate, a limitation in population growth as a function of population density. Density dependant factors may also affect population mortality and migration.

The ratio of live births in an area to the population of that area; expressed per 1000 population per year. The total births over a given period of a particular species, usually compared with the death rate to determine overall population movements.

also birth rate (bûrth′rāt′) The ratio of total live births to total population in a specified community or area over a specified period of time. The birthrate is often expressed as the number of live births per 1,000 of the population per year. Also called natality.

Cândido Godói is a village of 7,000 inhabitants in the south of Brazil that has a phenomenal number of twin births. The rate is ten times higher than the national average, and no one knows why.

Being pregnant after age 35 makes certain complications more likely, including premature birth, birth defects and getting pregnant with multiples. If you’re older than 35, you may want to have prenatal screening tests to see if your baby is at risk for certain birth defects.

Pain during labor is caused by contractions of the muscles of the uterus and by pressure on the cervix. This pain can be felt as strong cramping in the abdomen, groin, and back, as well as an achy feeling. Some women experience pain in their sides or thighs as well.