Recent declines in infant mortality in the US, 2005-2011

Background: After significant declines throughout the 20th century, the US infant mortality rate plateaued from 2000-2005.

Methods: The national mortality and linked birth/infant death data sets were used to analyze the recent decline in the US infant mortality rate from 2005-2011 by characteristics.

Results: The US infant mortality rate declined by 12%, from 6.87 infant deaths per 1,000 live births in 2005 to 6.05 in 2011. Declines were larger for non-Hispanic black than for non-Hispanic white or Hispanic women. Infant mortality declines were largest (20% or more) for states such as Louisiana, Georgia, the Carolinas and DC which previously had persistently high infant mortality rates, despite programmatic efforts. No states had a significant increase in infant mortality. Infant mortality declined significantly for four of the five leading causes of death: congenital malformations, sudden infant death syndrome (SIDS), short gestation/low birthweight and maternal complications. Infant mortality declined most rapidly for SIDS, although this decline may be due in part to changes in the way SIDS is diagnosed and reported. Declines for causes such as short gestation/low birthweight and maternal complications may be linked to a recent decline in the percentage of preterm births. Infant mortality rates from unintentional injuries did not decline from 2005-2011.

Discussion: The US infant mortality rate is higher than in most other developed countries, due in part to a high percentage of preterm births. Although the recent decline is encouraging, international comparisons show that there is still considerable room for further improvements in US infant mortality.