(CNN) Infant mortality rates have reached new lows, according to a report released by the US Centers for Disease Control and Prevention on Tuesday.
From 2005 to 2014, the infant mortality rate in the US dropped 15%, from 6.86 infant deaths per 1,000 live births to 5.82. Sudden infant death syndrome, or SIDS, declined by 29%, and there were drops in infant mortality rates across most racial groups.
"It's good news, but on the other hand, we have so much more to do," said Dr. Paul Jarris, chief medical officer for the March of Dimes, a nonprofit focused on the health of mothers and babies. "What is concerning, though, is that the inequities between non-Hispanic blacks and American Indians and the Caucasian population have persisted."
The largest drop among racial groups, 21%, was in Asian and Pacific Islander populations. All race and Hispanic subgroups experienced reductions in infant mortality rates except American Indians or Alaska Natives, among whom there was not a statistically significant change. The report shows significant declines among non-Hispanic black populations as well as women of Cuban descent.
However, those reductions were not broad enough to close the racial gap. Infants born to non-Hispanic black women have a mortality rate more than double that of non-Hispanic white women. Among Hispanic subgroups, the highest rates are seen in Puerto Ricans, 6.68 per 1,000, while the lowest, 3.95, are in populations of Cuban descent.
"I think there was a public health push in the past decade to figure out ways to lower this rate, and it has made an impact," said report author T.J. Mathews, a demographer at the CDC's National Center for Health Statistics. "We know that there have been a lot of efforts across the country in cities and states where they're trying to figure out ways where they can lower the infant mortality rate."
Rates for four of the five leading causes of infant death went down. Congenital malformations, the primary cause of infant death, dropped 11%. Deaths from short gestation and low birthweight declined 8%, deaths due to maternal complications fell 7%, and cases of SIDS fell 29%. Deaths caused by unintentional injuries increased 11%, from 26.2 in 2005 to 29.2 in 2014.
One source of the decline, Jarris said, is the push to end medically unnecessary induced labor. "These are when a woman is induced to cause labor when there is no medical indication. They were very common around 2003 to 2005, and we have done a good job as a nation of reducing these dramatically so that women aren't delivering early when there's no need."
Declines in infant mortality rates were observed in two-thirds of all US states and the District of Columbia, and no state reported a statistically significant increase. Infant deaths declined 11% percent or more in Colorado, Delaware, Idaho, Maryland, Mississippi, Nebraska, South Carolina, Tennessee, Virginia and the District of Columbia.
"Overall, 33 states and the District of Columbia had significant declines," Mathews said. "Some states with fairly high rates, such as South Carolina and Mississippi, are in those categories where they had some of the sharpest declines."
Although the report does not share details on how those states achieved lower rates, in the case of South Carolina, Jarris said the deliberate effort is key. "They have a strong partnership between the state Department of Health, the state Medicaid office, Blue Cross Blue Shield and the hospital association in which they are coordinating their efforts."
The decline, Mathews says, is a public health success.
According to the National Institutes of Health, since 1962, infant death rates in the United States have dropped more than 70%. Although rates continue to fall, the United States maintains one of the highest rates of infant death among developed countries.
"In terms of preterm birth and infant mortality, the United States has the highest rates of any of the developed nations," Jarris said. "Our rates are more similar to that of developing nations. So the message, from my point of view, is that we cannot be complacent."