AUTHOR=Shi Keqing , Cui Wenhui , Chen Shuyu , Zhang Xueli , Wang Xin , Cao Mengjun , Gao Hang , Wang Qiang 

TITLE=Effect of “universal two-child” policy on population changes in Shandong province, China: an interrupted time series analysis

JOURNAL=Frontiers in Public Health

VOLUME=Volume 13 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2025.1612141

DOI=10.3389/fpubh.2025.1612141

ISSN=2296-2565

ABSTRACT=BackgroundAs population aging intensifies and women’s fertility levels decline continuously, the improvement of fertility policies has emerged as a pivotal concern for most governments. This study aimed to evaluate the effect of the “universal two-child” policy implementation on the birth population trend.MethodsA quasi-experimental interrupted time series (ITS) study was conducted to analyze the collected data. Data on the birth population of Shandong province from 2000 to 2022 were collected to observe trend changes before and after the intervention.ResultsThe birth rate increased immediately in the first year after the intervention (p < 0.001), but the trend significantly declined in the following years (p < 0.001). After further adjustment for the influence of the pre-fertility policies, urbanization rate, and per capita disposable income, the birth population level still showed a downward trend year by year in the post-intervention period (p < 0.001).ConclusionThe policy implementation helped to boost the population growth in the short term, but the long-term effect of the policy was not optimistic. More targeted incentive strategies should be considered to reverse the continuous decline in fertility rates.