Transition in the Composition of Maternal Mortality in Korea: Implications for Extremely Low Fertility Societies

We examined long-term trends in age-specific and cause-specific maternal mortality and assessed shifts in the relative contributions of direct versus indirect obstetric causes from 1983 to 2023 in Korea.

In this population-based observational study, we analyzed all registered maternal deaths (International Classification of Diseases-10 O00-O99) among women aged 15-49 years and corresponding live births in Republic of Korea (= South Korea) from 1983 through 2023. Annual age-specific maternal mortality ratios (MMRs) per 100,000 live births were calculated using data from the Korean Statistical Information Service and the Causes of Death Statistics microdata of Statistics Korea. We classified deaths as direct or indirect obstetric causes and further disaggregated direct causes for the period 2009-2023. Proportions of direct versus indirect deaths were evaluated across five intervals (1997-2004, 2005-2009, 2010-2014, 2015-2019, and 2020-2023). Linear or segmented regression analyzed trends in overall MMRs and changes in the share of direct obstetric deaths.

All age groups showed marked declines in MMRs; women aged ≥ 40 years exhibited the greatest absolute reduction (from 249 to 38 per 100,000). The overall MMR ranged from 10.3 to 13.7 per 100,000 since the early 2000s. The proportion of direct obstetric deaths fell by 2.1 percentage points per year before 2011, then rose by 0.9 points annually afterward. From 2009 to 2023, other direct causes accounted for 24.1% of deaths, embolism 21.5%, hemorrhage 21.3%, and indirect causes 19.9%; hypertensive disorders (5.9%), sepsis (4.2%), and abortion complications (3.1%) comprised smaller shares. Indirect causes predominated in maternal deaths among younger women, whereas direct obstetric causes were more common in those aged ≥ 35 years.

Although age-specific MMRs in Korea have steadily declined, the stagnation of the overall rate and continued burden of direct obstetric causes underscore vulnerabilities in the country's emergency obstetric care infrastructure.