Trends in Syphilis Prevalence by Race and Ethnicity Among People Who Are Pregnant in the United States, 2016 to 2023.

BACKGROUND

This study aimed to estimate syphilis prevalence among people who were pregnant and delivered live births by race and ethnicity in 2016 to 2023.

METHODS

We analyzed data on syphilis infection from US birth certificates using a Bayesian mathematical model, adjusting for test sensitivity, specificity, and screening coverage. We calibrated the model under 2 scenarios: (1) assuming screening coverage is as estimated in Medicaid claims data and (2) assuming higher screening coverage than observed in Medicaid claims data. We also compared the prevalence estimates to stillbirths attributable to syphilis reported through routine surveillance. We examined racial and ethnic disparities using the index of disparity.

RESULTS

In scenario 1, syphilis prevalence among people who were pregnant and delivered live births increased from 101.1 (95% uncertainty interval [UI], 87.5-120.5) per 100,000 live births in 2016 to 533.4 (95% UI, 496.6-581.0) per 100,000 live births in 2023. In scenario 2, prevalence increased from 73.9 (95% UI, 51.2-130.0) per 100,000 live births to 378.1 (95% UI, 295.5-592.0) per 100,000 live births over the same period. With rising prevalence, relative racial and ethnic disparities narrowed over time. Prevalence was estimated to be higher among women with stillbirths compared with women with live births.

CONCLUSIONS

In the United States, syphilis prevalence among pregnant women has increased in all race and ethnicity groups. Improved estimates of screening coverage are needed to understand the gaps in congenital syphilis prevention and to inform estimates of syphilis prevalence among pregnant persons.