A Narrative Review of the Epidemiology of Congenital Syphilis in the United States From 1980 to 2019

Objectives Congenital syphilis (CS) is the result of antepartum transmission from mother to fetus of the spirochete Treponema pallidum. Although preventable through timely screening and treatment, the incidence of CS in the United States is increasing. This review describes the epidemiological trends in CS in the United States from 1980 to 2019 and characteristics of mothers of infants with CS. Methods We performed a narrative review of epidemiological studies of CS following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for reporting of observational studies in epidemiology. Quality and bias of included studies were assessed using the Newcastle-Ottawa Scale. Studies that described the demographics and characteristics of pregnant women with syphilis or who delivered an infant with CS in the United States were identified from PubMed and Embase. Results We identified a total of 2771 studies, of which 309 were selected for further review and 27 were included in the final analysis. Substance use during pregnancy was a risk factor for CS in 16 studies. Maternal cocaine use was described in 11 of the 16 studies, 10 of which were published between the years 1980 and 1999. No prenatal care was a risk factor for CS in 17 studies. Evidence of inadequate syphilis testing (i.e., no maternal screen, first screen after the first trimester, or no repeat screen in third trimester) or treatment (i.e., no treatment, treatment <30 days before delivery, or nonpenicillin treatment) was significantly associated with CS in 13 studies. Finally, higher rates of CS were reported among African American women in 11 studies. Conclusions Infection with and antepartum transmission of syphilis disproportionately affect certain subgroups of women. Women who report substance use during pregnancy are more likely to give birth to an infant with CS. No prenatal care and evidence of inadequate syphilis testing and treatment during pregnancy are also significantly associated with giving birth to an infant with CS. Finally, cases of CS disproportionately affect African American women. Addressing the CS epidemic will require identification and targeted allocation of resources to communities at elevated risk for syphilis, removal of barriers to prenatal care, and ensuring timely treatment and adequate partner notification of identified cases.