Congenital malformations as well as problems related to short gestation and low birthweight remained the leading causes of infant deaths in the United States in 2021, just as they were in 2020. The number of infants who died rose 2% in 2021 compared to 2020, but the infant mortality rate was flat.
That’s according to a National Vital Statistics Report from the Centers for Disease Control and Prevention released Tuesday.
Infant mortality is any death before the baby’s first birthday.
In all, 19,928 infants died in the United States in 2021. The infant mortality rate was 5.44 infant deaths per 1,000 live births, a statistically insignificant increase from 5.42 per 1,000 live births in 2020. The neonatal mortality rate was also unchanged, but the postneonatal death rate increased 5% from 1.86 to 1.95 per 1,000 live births.
Postneonatal deaths are those that occur 28 days or more after birth.
The numbers are primarily based on matching birth and death certificate data for infants younger than 1 who died from all 50 states, the District of Columbia, Puerto Rico and Guam.
The report said that U.S. infant mortality has “generally trended downward since 1995,” which was the first year that this particular data set was collected. It has declined 21% since its most recent high, which was in 2005.
Besides congenital malformities (20% of infant deaths) and complications of low birthrate and short gestation (15%), the most common causes of death included sudden infant death syndrome (7%), accidental injuries (7%) and maternal complications (6%).
With the exception of low birthweight and short gestation, a single category that saw a decline in infant mortality from 87.2 to 80.7 per 1,000 live births, the rate changes in each category from 2020 to 2021 were not significant.
Race, maternal age and other factors
By race, the infants of Black non-Hispanic women had the highest mortality rate (10.55), followed by non-Hispanic infants of Native Hawaiian or Pacific Islander women (7.76), American Indian or Alaska Native non-Hispanic women (7.46), Hispanic women (4.79), white non-Hispanic women (4.36) and Asian non-Hispanic (3.69) women.
The highest mortality rate by gestational age was among infants who were born prior to 28 weeks of gestation, which is considered very premature, at a rate 170 times that of infants born at term, which is 37 to 41 weeks of gestation.
Among the states, North Dakota had the lowest infant mortality rate in 2021 at 2.77 per 1,000 live births, while the highest rate was in Mississippi at 9.39 per 1,000 live births. In Utah, the infant mortality rate was 4.58.
Besides Mississippi, the states with the highest infant mortality were Arkansas (8.59), Alabama (7.56), Alaska (7.37), South Carolina (7.26), Louisiana (7.24), Oklahoma (7.13), Ohio (7.06), West Virginia (6.80) and Indiana (6.75).
According to the CDC, there were no significant infant mortality rate changes within maternal age groups. But the rates were highest in 2021 for infants with very young mothers, under age 15. The lowest infant mortality rate was among women ages 30-34.