Racial and Ethnic Disparities in Infant Mortality Rates Among Infants Born Preterm in the US Beyond 44 Weeks of Postmenstrual Age.

Objective: To investigate racial and ethnic disparities in the incidence of infant mortality, timing, and cause of death among infants born preterm in the US who survive to 44 weeks of postmenstrual age (PMA).

Methods: Retrospective cohort analysis using linked national birth and death certificate data from 2005 to 2014. Univariable and multivariable analyses were used to assess the associations between race and ethnicity and mortality rate, and timing of death. Descriptive analysis was used to examine differences in cause of death.

Results: Among 3 979 512 infants born preterm, the mortality rate and adjusted odds of death were greatest for American Indian/Alaskan Native (AI/AN) and Non-Hispanic Black (NHB) infants (aOR 1.62; 95% CI 1.43-1.83 and aOR 1.45; 95% CI 1.40-1.51, respectively) compared with Non-Hispanic White (NHW) infants. In addition, AI/AN and NHB infants experienced divergence in survival rates from 44 to 60 weeks of PMA. Sudden unexpected infant death was the leading cause of death for AI/AN, NHB, and NHW infants born preterm.

Conclusions: Significant disparities in preterm infant mortality rate at postterm corrected gestational age persist. Further research is needed to examine contributory factors for these racial and ethnic differences in timing and cause of death.