The crude birth rate (which measures the number of children born each year per thousand population) and the total fertiliy rate (number of children per woman can be found in the people category.

Birth rate and life expectency are the major factors affecting total population. Countries with a high birth rate and low life expectency generally have a large number of young people.

Most developed countries have low birth rates. Globally 89 countries (including all European and North American countries except Faeroe Islands, Albania and Mexico) have fertility rates below population replacement. This means that their populations would be shrinking if there was no immigration to these countries.

In developing nations, infections during pregnancy and after birth cause an estimated 1.6 million deaths annually, three-quarters of them in southern Asia and sub-Saharan Africa. Many infections are caused by methicillin-resistant staphylococcus aureus (MRSA), while another major killer is the organism Klebsiella pneumoniae, which kills an estimated 320,000 infants and unborn babies each year in the developing world.

Up to 70 percent of these infections are believed to be caused by superbugs – bacteria resistant to antibiotic treatment.

Neonatal deaths account cause more than a third of all child mortality across the world.

Deaths of infants aged zero to 27 days increased by 4.4 percent from 2001 to 2002. The postneonatal mortality rate (deaths to infants aged 28 days to one year per 1000 live births) remained constant at 2.3.

The 10 leading causes of infant death were: 1) congenital malformations, deformations and chromosomal abnormalities; 2) disorders related to short gestation and low birth weight; 3) Sudden Infant Death Syndrome (SIDS); 4) maternal complications; 5) complications of placenta, cord and membranes; 6) unintentional injuries; 7) respiratory distress of newborn; 8) bacterial sepsis of newborn; 9) diseases of the circulatory system; 10) intrauterine hypoxia and birth asphyxia.

These 10 causes accounted for 68.4 percent of all infant death in the U.S. There were significant increases in deaths attributed to low birth rate (5.3 percent) and maternal complications (14.2) percent.

• Congenital malformations, deformations and chromosomal abnormalities. These account for 20 percent of cases
• Disorders related to short gestation and low birth weight alone account for 16 percent of cases
• SIDS (Sudden Infant Death Syndrome) which accounts for 8
  percent.

All of these occur more often when maternal health and nutrition are poor. In many cases, causes are multiple with low birth weight being a major factor.

Infant mortality is highest in developing nations. These countries generally have a low href=/graph/eco_gdp>GDP, low literacy,
high levels of poverty, a high rate of maternal mortality and a high number of children per woman.