Surveillance of Maternal Syphilis in China: Pregnancy Outcomes and Determinants of Congenital Syphilis

Background: We sought to describe the epidemiological characteristics of pregnant women with syphilis in Beijing, China, and to investigate the determinants of adverse pregnancy outcomes, including congenital syphilis. Material/Methods: We used data from laboratory-confirmed syphilis-infected women who delivered between 2013 and 2015 and were registered in China's Information Management System for Prevention of Mother-to-Child Transmission of Syphilis. Sociodemographic, clinical, and prevention predictors of adverse pregnancy outcomes (i.e., congenital syphilis, neonatal death, and neonatal asphyxia) were assessed using multivariable regression analyses. Results: Among 807 eligible pregnant women with syphilis in Beijing, the maternal syphilis ratios increased from 1.1 (in 2013) to 1.4 (in 2015) per 1000 live births, while adverse pregnancy outcomes decreased, including congenital syphilis (1.3% to 0.4%), neonatal deaths (1.3% to 0%), and neonatal asphyxia (0.9% to 0%). Both prevention and treatment interventions increased, including antenatal testing (93.5% to 93.9%), any treatment (76.6% to 85.2%), adequate treatment (51.1% to 65.1%), and treatment initiated in the first trimester (30.7% to 42.8%). In the logistic regression analysis, higher maternal rapid plasma reagin antibody titers (aOR=1.1 95%Cl=1.0-1.1) and third-trimester syphilis diagnosis (aOR=1.7 95%Cl=1.1-2.6) were independent risk factors for adverse pregnancy outcomes. Protective factors included being married (aOR=0.4; 95%Cl=0.2-0.6) and adequate prenatal treatment (aOR=0.3; 95%Cl=0.1-0.7). Conclusions: Integrated strategies for maternal syphilis control were associated with improved outcomes but must be strengthened. Future efforts should include education and outreach for antenatal care for at-risk women, syphilis screening at first antenatal care visit, immediate initiation of treatment, and syphilis screening extended to women presenting with miscarriage or stillbirth.