Syphilis cases among pregnant women and newborns in the Military Health System, 2012-2022

This report presents the rates of maternal syphilis among pregnant women and congenital syphilis among newborns in the Military Health System (MHS) beneficiary population from 2012 to 2022. Medical encounter data from military hospitals and clinics as well as civilian health care facilities were obtained from the Defense Medical Surveillance System (DMSS) to determine pregnancies, live births, and confirmed diagnoses of maternal and congenital syphilis. The rate of maternal syphilis in female MHS beneficiaries increased by 233% between 2012 (n=123, 66.0 per 100,000 births) and 2022 (n=169, 219.8 per 100,000 births), while the rate of congenital syphilis in newborn MHS beneficiaries increased by 355% (n=9 to n=32, 6.8 to 30.8 per 100,000 live births). Pregnant active component service members generally evinced higher rates of maternal syphilis than pregnant non-service member MHS beneficiaries during the reporting period. Additionally, the positive predictive value of maternal syphilis cases in the MHS was found to be low (59%). Future studies could focus on potential misclassification of maternal syphilis cases as well as syphilis screening compliance and treatment during pregnancy for all pregnant MHS beneficiaries. The rate of diagnosed maternal syphilis among pregnant female active component service members exceeded previously reported rates of syphilis among all female active component service members annually between 2015 and 2022, likely due to increased screening.