The overall infant mortality rate in the United States did not change much from 2011 through 2016, after declining 10% from 2007 through 2011, according to new data from the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC).
Rates of total infant mortality as well as neonatal mortality (infants aged 0-27 days) and postneonatal mortality (infants aged 28-364 days) in 2016 were generally unchanged from 2015, the authors report.
The total infant mortality rate declined from 6.75 infant deaths per 1000 births in 2007 to 6.07 in 2011, but was relatively stable through 2016 at 5.87 deaths per 1000 births.
The neonatal mortality rate declined from 4.42 in 2007 to 1.87 in 2014, but was essentially unchanged between 2015 and 2016 (3.94 deaths per 1000 births). The postneonatal mortality rate declined from 2.33 in 2007 to 1.87 in 2014 and held steady from 2014 (1.87) through 2016 (1.99).
Total infant, neonatal, and postneonatal mortality rates in the United States continue to vary by maternal characteristics such as mother’s race and Hispanic origin and age.
In 2016, neonatal mortality rates were highest among infants of non-Hispanic black women (7.41), while postneonatal mortality rates were highest among infants of non-Hispanic black (3.81) and American Indian or Alaska Native (3.93) women.
Neonatal mortality rates were highest among infants born to women younger than age 20 years and women aged 40 years and older compared with infants of other maternal age groups. Postneonatal mortality rates were highest among infants of women younger than age 20 years.
“This pattern reflects risk factors for infant death among women under age 20 and aged 40 and over, such as higher rates of low birthweight and preterm births and lower rates of timely prenatal care,” the authors note.
Neonatal and postneonatal infant deaths are largely due to different causes, they report.
Among the five leading causes of neonatal death, low birthweight had the highest rate (97.7 neonatal deaths per 100,000 births), followed by congenital malformations (86.4), maternal complications (35.3), placenta/cord/membrane complications (21.0), and bacterial sepsis (14.0).
Neonatal mortality rates for low birthweight and congenital malformations were two to seven times higher than rates for the other three causes.
Among the five leading causes of postneonatal mortality, congenital malformations and sudden infant death syndrome (SIDS) accounted for the highest rates (35.8 and 34.9 per 100,000, respectively), followed by unintentional injuries (27.4), diseases of the circulatory system (9.1), and homicide (6.4).
Postneonatal mortality rates for congenital malformations and SIDS were three to six times higher than rates for circulatory diseases and homicide.