After years of decline, the number of births has risen in both 2024 and 2025, raising expectations that births may continue to rise in the long term. Determining whether this increase represents a temporary upswing or a harbinger of a long-term structural shift requires an in-depth demographic analysis.
A time series analysis of birth trends since 2015 has identified a rebound in 2024-2025 following the long-term decline observed through 2023. Our demographic decomposition analysis indicates that the recent increase in births is attributable to demographic shifts―particularly growth in the number of women in their early 30s―and changes in marriage and fertility patterns, reflecting the gradual clearing of the backlog of marriages postponed during the COVID-19 pandemic and increases in marital fertility.
However, the shrinking female population aged 15-49, the increasing age at first marriage and childbirth, and the rising proportion of married couples without children remain factors that may prevent the increase in births from continuing. Therefore, sustaining this momentum in the long term would require continuous monitoring of birth trends and in-depth analysis of age-group-specific dynamics, in order to implement structural changes that create conditions conducive to marriage and childbearing among young adults.