Abstract: Objective To understand the infection-related characteristics of syphilis-infected pregnant women in East China and its associated factors.Methods Data of syphilis-infected pregnant women in East China from the national ‘Information System of Prevention of Mother-to-child Transmission of HIV, syphilis and HBV Management’ were analyzed in our study. We described the demographic and infection-related characteristics and non-treponemal titer. We analyzed factors associated with non-treponemal titer using logistic regression model.Results There were 9101 syphilis-infected pregnant women in East China in 2015. There were 4613 (50.7%) women who received antenatal care visit in their first trimester of pregnancy, while only 2805 (30.8%) were diagnosed during the first trimester. There were 5640 (62.0%) women that were unware of their route of infection. Syphilis infection status of 5954 (65.4%) women'shusband/partners were unknown. High level of none-treponemal titer (≥ 1:8) was associated with age, marriage status, education, first antenatal care visit, syphilis infection history and husband/partner infection status.Conclusion Diagnosis delay of maternal syphilis was not rare among pregnant women. The infected pregnant women were at risk of re-infection. We suggest to further reduce congenital syphilis risks by continuing optimizing prevention of mother-to-child transmission care, standardizing counselling, diagnosis, treatment and follow-up practices, and promoting testing uptake in partners.