Trends in neonatal mortality on the first day of life in Japan, Korea, and Taiwan.

BACKGROUND: Studies have indicated that the risk of death on the first day of life (day 0) was higher than risk of death during other periods (days 1 to 6 and 7 to 27). However, little is known about whether the pattern of mortality trends on day 0 differs from those on days 1 to 6 and 7 to 27. We aimed in this study to examine NMRs trends by age at death in Japan, Korea, and Taiwan. METHODS: In this cross-sectional study, we calculated NMRs (deaths per 1000 live births) by age at death from 2005 to 2021 in Japan, 2005 to 2022 in Korea, and 2005 to 2023 in Taiwan. Joinpoint regression model was used to estimate the annual percent change (APC) for each segment of the trend in NMRs to examine whether the trend changed significantly. RESULTS: A slowdown of decreasing trend on days 0 to 27 was observed from 2015 to 2021 with APC of - 4.3% to - 1.5% in Japan and from 2008 to 2018 with APC of - 8.5% to - 1.4% in Korea. In contrast, an initial decline followed by an increase pattern of trend was noted in Taiwan with APC of - 2.5% from 2005 to 2014 to 2.1% from 2014 to 2023. In Japan, the slowdown was mainly due to the levelling-off in the decline in NMRs for days 1 to 6. In Korea, the slowdown was mainly attributed to the levelling-off in the decline in NMRs for days 7 to 27. In Taiwan, the prominent change was primarily due to the changes in day 0 NMRs. CONCLUSIONS: Further analyses are needed to explore potential factors associated with the particular pattern of trends of NMRs at specific age-at-death group. Neonatal mortality on the first day of life is not an appropriate indicator of neonatal care quality, as it may be influenced by artifacts related to birth certification practices.