(P280) Prenatal syphilis and HIV screenings in the early third trimester have increased following new legislation in Michigan

Background

Nationally, the reported rate of congenital syphilis has tripled during 2017 (24.4 per 100,000 live births) through 2021 (74.1), similar to Michigan (2017, 12.6; 2021, 40.0). Congenital syphilis is preventable if a pregnant person is screened and treated at least 30 days before delivery. In December 2018, new legislation was passed in Michigan requiring first and third trimester prenatal syphilis and HIV screening. We evaluated annual trends in prenatal screenings to determine the law’s impact.

Methods

We analyzed claims data from Medicaid enrollees who were women, aged ≥12 years, residents of Michigan, and had delivered an infant during 2017—2021. Established algorithms (SYMMETRY) flagged syphilis and HIV tests occurring within 280 days preceding delivery. Two screening patterns were defined based on the number of days before delivery when testing did or did not occur: ‘new law’ (280—94 days and 93—62 days) and ‘early third trimester gap’ (280—94 days and not 93—62 days). As well, two distinct periods (280—94 days; 93—62 days) were evaluated separately to determine whether either period drove trends in the ‘new law’ screening pattern. Trends were evaluated by calculating the absolute percentage change over time; changes < +/-10% were considered stable.

Results

Of the 148,032 women analyzed, most were aged 20—29 years (60.7%), white (51.9%) or Black (35.2%) race. The percentage ever screened was stable (change, -0.4%) for syphilis (2017, 92.3%; 2021, 91.9%) and HIV (change, +4.3%; 2017, 86.8%; 2021, 91.1%). Screening in accordance with the ‘new law’ increased by 12.0% for syphilis (2017, 30.1%; 2021, 42.1%) and 11.3% for HIV (2017, 29.3%; 2021, 40.6%); these changes were driven by the 93—62 days period (syphilis, change, +13.0%; HIV, change, +12.5%) and not the 280—94 days period (syphilis, change, -1.7%; HIV, change, +3.0%). The ‘early third trimester gap’ pattern decreased for syphilis (change, -13.8%; 2017, 53.8%; 2021, 40.0%) but was stable for HIV (change: -8.1%; 2017, 48.7%; 2021, 40.6%).

Conclusion

Repeat prenatal syphilis and HIV screenings in the early third trimester have modestly improved following new legislation. Continued efforts are needed to raise awareness of repeat third trimester screening.