Birth rate, or crude birth rate, is defined as the ratio of live births in an area versus the population of that area.

It is expressed as the number of live birth per 1000 population (at mid-year) per year.

The birth rate, death rate, and net migration in a country determine the country’s population growth.

See also

• Factors affecting birth rate
• Birth rates in the USA

Some of the factors that affect the birth rate in a given country include:

• Governmental policies (whether the government is pro-natalist or anti-natalist) - Countries like Japan and Thailand have natalist governments giving their citizens special incentives for bearing more children. China’s one-child only policy is the perfect example of anti-natilism.
• Social Beliefs - This is usually heavily intertwined with religious beliefs since the predominant religion in the region affects society. Birth statistics can become skewed where there is gender/sex preference. For example, in certain countries female children are deemed worthless so that killing female infants before their births are even declared is common enough to affect birth statistics.
• Religious Beliefs - Countries wherein the predominant religious belief is against contraception can be expected to have higher birth rates.
• Abortion Rates - Abortion rates are affected by the other factors that affect birth rate.
• Poverty/Economic prosperity - The ironic thing with this factor is that even though those that are more prosperous can afford to have more children they are usually the ones that have less, while poor families often have more children.
• Literacy (with special emphasis on female literacy)
• Infancy mortality rate - Countries with higher infant mortality rates generally have higher birth rates since families make it a point to have more children since the children are more likely to die.
• Conflict - Pertaining to war, security, safety.
• Urbanization.

For the past fourteen years the birth rate in the United States has been significantly falling with the all-time low happening in 2002.

The decline in birth rate started in 1991 and continued until 2005. However, during the last two years the trend has reversed and birth rates are on the upswing again. Although birth rates of all age levels have increased, of greatest concern to authorities is the rise in teen birth rate (3%) from 2005 to 2006 even if it has decreased by 34% during the 14-year decline.

The reasons for this reversal of the trend is still unclear although many are blaming complacency as well as the ineffectiveness of sex education.