Disparities and Temporal Trends in Syphilis Testing Among Pregnancies Ending in Stillbirth and Miscarriage, U.S., 2016-2023

Syphilis during pregnancy represents a significant public health issue in the U.S., leading to rising rates of congenital syphilis and preventable adverse outcomes such as stillbirth and miscarriage. However, the understanding of syphilis screening/testing among pregnancies ending in stillbirth and miscarriage is limited. The purpose of this study was to analyze the monthly trends of syphilis screening/tetsing among pregnancies ending in stillbirth and miscarriage.

A retrospective longitudinal study was conducted using the Marketscan® Commercial Claims and Encounters Database from 2015 to 2024. To identify pregnancies ending in stillbirth and miscarriage, validated ICD-10, CPT-4, and HCPCS codes were used. Monthly syphilis screening/testing rates were identified and summarized at any point during the prenatal care and at delivery, stratified by age, region, and urban/rural residence. Temporal trends were assessed using generalized linear mixed models with a Poisson distribution.

Syphilis screening/testing among pregnancies ending in stillbirth remained stable, with no notable changes. Prenatal syphilis screening ranged from 72% to 90%, while at-delivery testing ranged from 5% to 15%. Testing during the at-delivery window was higher in the South and lower in rural areas. Syphilis screening/tetsing among pregnancies ending in miscarriage was consistently low.

Syphilis screening/testing among pregnancies ending in stillbirth and miscarriage remains insufficient, with no improvement over time. Ongoing gaps and disparities in screening/testing may contribute to preventable adverse outcomes. A deeper understanding of the ongoing low screening/testing rates and disparities is needed to support the development of more focused and effective strategies to improve syphilis screening coverage.