Abstract: 【Abstract】 Objective To analyze the epidemiological trends and spatiotemporal patterns of reported syphilis incidence among women of childbearing age （15 - < 50 years） in China from 2010 to 2025. Methods Data on reported syphilis cases among women of childbearing age in 31 provinces, autonomous regions, and municipalities in China, stratified by age, were collected from the Infectious Disease Reporting Information Management System of the Chinese Center for Disease Control and Prevention from 2010 to 2025. Joinpoint regression models were used to calculate the average annual percentage change （AAPC） in incidence rates. With prefecture-level administrative units as the geographical analysis units, ArcGIS software was used to calculate global Moran's I and the Getis-Ord General G statistic for spatial autocorrelation and the Getis-Ord Gi* statistic for hotspot analysis, and SaTScan was used with the discrete Poisson model for space-time scan analysis. Results From 2010 to 2025, the reported incidence rate of syphilis among women of childbearing age （15 - < 50 years） in China exhibited a fluctuating trend overall, with the incidence rates in 2010 and 2025 being 39.36 per 100 000 and 39.88 per 100 000, respectively （AAPC = 0.05%, P = 0.86）; specifically, the reported incidence rate of primary and secondary syphilis decreased from 19.07 per 100 000 in 2010 to 3.27 per 100 000 in 2025 （AAPC = -11.73%, P < 0.001）, whereas the incidence rate of latent syphilis increased from 20.13 per 100 000 to 36.56 per 100 000 （AAPC = 4.38%, P < 0.001）. Age-stratified analysis showed that the reported incidence rate of syphilis in the age group of 15 - < 25 years increased from 31.99 per 100 000 in 2010 to 51.70 per 100 000 in 2025 （AAPC = 4.49%, P < 0.001）; in the age group of 25 - < 35 years, it decreased from 64.16 per 100 000 to 38.92 per 100 000 （AAPC = -4.19%, P < 0.001）; in the age group of 35 - < 50 years, it fluctuated from 30.61 per 100 000 to 34.79 per 100 000 （AAPC = 0.77%, P = 0.09）. The incidence rates showed significant positive spatial autocorrelation （Moran′s I: 0.31 - 0.63, all P < 0.001） and high-value clustering （Z ［G］: 10.32 - 18.85, all P < 0.001）. Each year, 31 to 59 prefecture-level administrative units were identified as hotspots, primarily located in Xinjiang, Qinghai, Sichuan, Yunnan, and Hainan. A total of 35 statistically significant clusters were identified by space-time scan analysis; from 2010 to 2017, these clusters were mainly located in Zhejiang and Fujian; from 2018 to 2025, they were mainly located in Xinjiang, Qinghai, Sichuan, and Xizang. Conclusion From 2010 to 2025, the reported incidence rates of primary and secondary syphilis among women of childbearing age （15 - < 50 years） in China showed a downward trend, and the epidemic exhibited distinct spatiotemporal clustering. The hotspot areas closely coincided with the spatiotemporal clusters, and were mainly distributed in the southeastern coastal, northwestern, and southwestern regions; the spatiotemporal clusters gradually shifted from the southeastern coastal areas to the northwestern and southwestern areas over time.

Key words: Syphilis, Women of childbearing age, Incidence rate, Epidemiological characteristics, Spatiotemporal distribution