Implementation and performance of a national pilot programme for eliminating mother-to-child transmission of syphilis: a retrospective cross-sectional study in China.

BACKGROUND: Syphilis remains a significant global health burden, with congenital syphilis (CS) posing a major threat to child health. China has implemented the elimination of mother-to-child transmission (EMTCT) programme for syphilis through integrated strategies. However, few studies have analysed granular data along the entire cascade of care to identify specific bottlenecks. OBJECTIVE: We aimed to characterise the implementation status of integrated interventions in Baoan District, Shenzhen, and to identify risk factors associated with suboptimal indicators. METHODS: This retrospective cross-sectional study used data from the information system for the prevention of mother-to-child transmission of syphilis in Baoan District (2017-2024). Indicators were compared between the pre-practice (2017-2018) and post-practice (2019-2024) periods using Pearson's χ² test. Joinpoint regression models were used to estimate annual percentage change (APC) during the post-practice period. Univariate and multivariable logistic regression analyses were used to identify factors associated with indicators failing to meet predefined targets. RESULTS: A total of 752 pregnant women with syphilis and 769 exposed liveborn infants were finally included. Compared with the pre-practice period, significant upward trends were observed in the post-practice period across all process indicators (all p<0.05), while no statistically significant decline in live birth CS incidence was observed between the two periods (2.92 vs 1.59 per 100 000 live births, p=0.70). During 2019-2024, antenatal screening coverage (APC=0.23, p=0.01) and first-trimester screening coverage (APC=6.79, p=0.01) showed significant upward trends. However, adequate treatment coverage plateaued (APC=0.41, p=0.67), with the 2024 rate of 87.74% (below the 90% target). Multivariable analysis identified four independent risk factors for inadequate treatment: ethnic minority background (aOR=2.41, 95% CI 1.09 to 5.35), first antenatal visit at ≥13 weeks (aOR=2.30, 95% CI 1.09 to 4.84), <5 antenatal visits (aOR=3.14, 95% CI 1.55 to 6.33) and partner not tested for syphilis (aOR=2.07, 95% CI 1.07 to 4.01). CONCLUSIONS: EMTCT process indicators showed favourable trends during the integrated implementation period in Baoan District. However, gaps in achieving the treatment adequacy target highlight critical bottlenecks. Targeted interventions for high-risk populations, including ethnic minorities, women with late or insufficient antenatal care and those with untested partners, are essential to further achieve EMTCT goals.