September 26, 2014 — The U.S. infant mortality rate has improved but was still the fourth highest among 29 developed nations included in a CDC report released on Wednesday, the Los Angeles Times' "Science Now" reports (Kaplan, "Science Now," Los Angeles Times, 9/24).
For the report, the infant mortality rate was defined as the percentage of infants who were born alive but died prior to their first birthdays. The researchers compared 2010 U.S. infant mortality rates with European countries, as well Australia, Korea, Israel, Japan and New Zealand.
CDC found that the U.S. infant mortality rate had declined from 6.87 infant deaths per 1,000 live births in 2005 to a rate of 6.1 in 2010 (Haelle, HealthDay/U.S. News & World Report, 9/24). By comparison, the lowest 2010 rates identified in the study were 2.3 in Finland and Japan and 2.5 in Portugal and Sweden.
However, some countries did not report infant mortality rates for premature infants born at 22 or 23 weeks of gestation ("Science Now," Los Angeles Times, 9/24). When excluding such infant deaths from the data, researchers found that the U.S. infant mortality rank was 4.2 deaths per 1,000 live births, the ninth highest rate among countries that supplied infant mortality data for infants born at 22 or 23 weeks and about double the rates for Denmark, Finland and Sweden (Adams, CQ HealthBeat, 9/23).
Overall, the U.S. had the fifth-lowest rate for infants born after 24 to 27 weeks, the second-highest rate for infants born after 32 to 36 weeks, and the highest rate for infants born after at least 37 weeks, with 2.2 deaths per 1,000 live births.
Rates in Perspective
The researchers said that if the U.S. could reduce its mortality rate for infants born after at least 37 weeks to Sweden's rate of 1.1, the country's overall infant mortality rate could decline to 3.2, which would be equivalent to 4,100 fewer infant deaths annually.
In addition, CDC said that if the percentage of all births in the U.S. involving infants born preterm -- before 37 weeks -- declined from 9.8% to Sweden's rate of 5.8%, the U.S. infant mortality rate would decline to 3.4, which would be equivalent to 3,200 fewer infant deaths annually ("Science Now," Los Angeles Times, 9/24).
Contributors to U.S. Rates
Lead author Marian MacDorman said that while the researchers expected the U.S. to have a high preterm birth rate, the "higher infant mortality rate for full-term, big babies who should have really good survival prospects is not what we expected."
While noting that the report did not provide a reason for the findings, MacDorman suggested that they were the result of "social factors, such as [sudden infant death syndrome] and injuries," adding, "I don't think it's so much about health care but about the environment and raising a child."
Deborah Campbell -- a professor of clinical pediatrics at Albert Einstein College of Medicine who was not involved in the study -- said the relatively high infant mortality rate in the U.S. is the result of "significant gaps in access to and utilization of prenatal and preconception care." She added that black women and their infants, in particular, have had a higher risk of mortality as the result of issues such as discrimination, malnutrition and a lack of access to quality care (HealthDay/U.S. News & World Report, 9/24).