Syphilis Screening Among Commercially-Insured Pregnant Women in the United States

Background: Congenital syphilis (CS) incidence increased by 81.7% in the United States (US) between 2020 and 2024. Syphilis screening is recommended at the first prenatal visit and at delivery, but poor compliance may lead to inadequate screening and preventable CS cases. Methods: Using a US-wide collection of longitudinal healthcare claims data, we identified a cohort of commercially-insured pregnant women aged 15-44 years. Women were included if they had a pregnancy resulting in a live birth, stillbirth, or spontaneous abortion during 2017-2021. We described patterns of syphilis screening, diagnoses, and treatment. We also linked women to their infants and examined missed opportunities for CS prevention. Results: Of 728,674 pregnant women, 79.2% received ≥1 syphilis test during pregnancy, and 53.0% received multiple tests. In the first, second, and third trimesters, 41.5%,17.2%, and 31.8% were screened, respectively. The proportion of women receiving ≥1 syphilis test increased by 4.5% between 2017-2021. The median time from pregnancy start to first syphilis screening among those who had any screening was 73 (IQR 56-169) days. Thirty-one women delivered infants with CS. Of these, 28 (90.3%) were screened during pregnancy, 9 (29.0%) were diagnosed with syphilis before delivery, and 6 (19.4%) had documented treatment. Conclusion: These data indicate a systematic gap in syphilis screening among pregnant women, especially in the first trimester, when timely screening may allow for early intervention. Most pregnant women were only screened once, reducing providers’ ability to identify syphilis infections. Improved prenatal screening is essential to addressing the CS epidemic.