(302) Prenatal syphilis in the US: characterizing screening and treatment during pregnancy in publicly and commercially insured individuals

Background: Cases of congenital syphilis have risen 10-fold in the US between 2012-2022. Lack of screening and adequate treatment for syphilis during pregnancy, often due to a lack of timely prenatal care, are the most cited reasons for transmission to the neonate.

Objectives: To assess syphilis screening and treatment during pregnancy among publicly and commercially insured pregnant individuals in the US.

Methods: Pregnancies in individuals aged 10-55 years with singleton live births and continuous insurance coverage throughout pregnancy were identified in the Sentinel Distributed Database, which includes claims data from Medicaid (2014-2020, N=2,787,710) and commercially insured patients (2010-2023, N=3,366,779). Timing of syphilis screening was assessed by trimester and at delivery (delivery date or 7 days after). Among pregnancies screened and diagnosed with syphilis, recommended treatment was defined as receiving benzathine penicillin G. Non-recommended treatments included other antibiotics dispensed within 30 days of a syphilis diagnosis code, with no documentation of benzathine penicillin G.

Results: Among the Medicaid and commercially insured pregnancies, 75.0% and 92.7%, were screened for syphilis during pregnancy or at delivery, respectively. Screening prevalence increased only slightly over time (71.3-78.5% from 2016-2020 in Medicaid; 90.9-93.8% from 2010-2023 in commercially insured). Most were initially screened in the 1st trimester (51.0% in Medicaid, 81.7% in commercially insured); this increased to 67.5% and 88.0%, respectively, among those with 1st trimester prenatal care. In Medicaid, 17.5%, 6.0%, and 0.4% were initially screened in the 2nd trimester, 3rd trimester, and at delivery, respectively. The corresponding results among commercially insured were 9.1%, 1.6%, and 0.4%. Among screened Medicaid-insured pregnancies with syphilis diagnosis (0.5% of all screened), 27.9% had recommended treatment and 3.6% had non-recommended treatment. Among commercially insured, syphilis diagnosis and treatment were lower; 0.1% screened had a diagnosis, of which 13.0% had recommended and 3.3% had non-recommended treatment.

Conclusions: Most pregnancies were screened for syphilis in early pregnancy; however, despite insurance throughout pregnancy, 25% of Medicaid insured and 7% of commercially insured had no evidence of screening in pregnancy or at delivery. Treatment with benzathine penicillin G was uncommon; this may be due to misclassification of syphilis cases or treatment received outside of insurance reimbursement (e.g., in health departments). Given the lack of improvement in screening over time and the notable disparities by insurance type, targeted strategies to improve screening in pregnancy are urgently needed.