Change in the Primary Measure of Perinatal Mortality for Vital Statistics.

Abstract

Background and objectives: Beginning with the 2023 data year, the National Center for Health Statistics (NCHS) will use a different, expanded measure of perinatal mortality for standard publications. This measure, Definition III, includes fetal deaths at 20 weeks of gestation or more and infant deaths younger than 7 days. Definition III replaces Definition I (fetal deaths at 28 weeks of gestation or more and infant deaths younger than 7 days), which has been used in NCHS reports since the 1980s. This change is being made due to the implementation of national reporting of all fetal deaths at 20 weeks of gestation or more as of 2014, allowing for the use of Definition III, which more fully represents the perinatal events most likely to be affected by similar factors. This report describes the reason for this change and compares trends in perinatal mortality rates based on Definition I and Definition III from 2014 to 2022 and differences in the two measures by maternal race and Hispanic origin, age, and state of residence for 2022.

Methods: Data for perinatal mortality are derived from NCHS's National Vital Statistics System's fetal death, birth, and period linked birth/infant death files. Perinatal mortality rates for Definition III are compared with those for Definition I.

Results: In 2022, Definition III comprised 91.4% of perinatal deaths (fetal deaths at 20 weeks of gestation or more and infant deaths younger than 28 days) compared with 60.7% of perinatal deaths captured by Definition I. The perinatal mortality rate for Definition III was about 50% higher than that for Definition I (8.27 and 5.51, respectively, in 2022). Trends in perinatal mortality were similar for both measures during 2014-2022; rates were stable from 2014 through 2016 and then declined from 2016 through 2022. For 2022, patterns by maternal race and Hispanic origin and age were also similar, but more variation in patterns was observed by state.