Life expectancy for a child born in 2007 in the U.S. reached a record high of 77.9 years. (Carolyn Ryan/CBC)

The number of births in the U.S. increased in 2007 to more than 4.3 million, according to a new report.

Recorded births increased one per cent from 2006, researchers from the U.S. Centers for Disease Control and Prevention said in Monday's online issue of the journal Pediatrics.

Teen births increased five per cent between 2005 and 2007, after a 34 per cent decline occurred between 1991 to 2005.

In 2007, the last year for which figures are available, the birth rate among U.S. teens rose by about one per cent, with 42.5 babies born for every 1,000 teens aged 15 to 19.

The U.S. infant mortality rate in 2007 did not change much from the year before, when it reached 6.7 deaths per 1,000 live births. The rate remained higher than in many other countries, including France at 3.6 deaths per 1,000, 2.6 deaths per 1,000 in Japan.

In 2005, Canada's infant mortality rate was 5.4 deaths per 1,000 live births, the latest year for which figures were reported by the United Nations.

In 2005 in the U.S., there were wide variations in infant mortality rates according to race and Hispanic origin, the study's authors said. The highest rate, 13.63 deaths per 1,000 live births for infants of non-Hispanic black mothers was more than double the rate of infants born to non-Hispanic white mothers at 5.76 deaths per 1,000 live births.

In March, another team of researchers found the infant mortality rate for native babies in Canada, the U.S., Australia and New Zealand is four times that of non-native newborns.

A CDC report released in November pointed to the high percentage of preterm births in the U.S. as a possible reason why the infant mortality rate is higher in the United States than in Europe.

Infant mortality rates are considered a key indicator of the overall quality of a country's health-care system.

Other findings include:

• In 2007, there were 69.5 births for every 1,000 women of childbearing age in the United States.
• Nearly 32 per cent of babies were delivered by caesarean section, up two per cent from the year before.
• The percentage of births to unmarried women increased from 38.5 per cent in 2006 to 39.7 per cent in 2007.
• Life expectancy for a child born in 2007 reached a record high of 77.9 years.
• Death rates for children aged one to 19 fell 2.5 per cent.

The general fertility rate rose 1 per cent to 69.5 births per 1,000 women of childbearing age, with increases seen across across ethnic groups.