Clinical outcomes and management of syphilis during pregnancy amidst the Northern Territory syphilis outbreak: a 10-year retrospective cohort study

BACKGROUND: This retrospective study describes the clinical outcomes and management of people diagnosed with syphilis during pregnancy and their newborns at risk of congenital syphilis in the Northern Territory (NT), Australia between 2013 and 2023. METHODS: Demographic, clinical, and contact tracing information on all pregnancies with syphilis diagnosed prior to or during pregnancy, and clinical information of neonates, were sourced from spreadsheets and the NT Syphilis Register Information System. RESULTS: A total of 380 pregnancies were monitored, of which 186 pregnancies were identified as at risk of mother-to-child transmission of syphilis. Reinfection accounted for 13.8% of the 181 new syphilis infections. Of the 188 neonates, there were 11 cases of congenital syphilis, including 1 case of stillbirth. All congenital syphilis cases occurred when maternal syphilis was diagnosed in the third trimester or at the time of childbirth. While maternal treatment was completed in all pregnancies, 22 (11.8%) received treatment less than 30 days prior to childbirth or were untreated at the time of childbirth. Initial treatment was inadequate in 10 pregnancies (5.4%). A lack of four-fold reduction in rapid plasma reagin (RPR) titres by the time of childbirth due to delayed diagnosis and treatment was significantly associated with neonatal congenital syphilis (P < 0.001), with a median RPR of 1:8. Among identified contact/s, 54 (43.2%) tested positive for syphilis. CONCLUSION: Early detection, treatment, and follow-up of maternal syphilis before and during pregnancy are key measures to prevent congenital syphilis. Universal syphilis screening with repeat testing should be incorporated into antenatal care to minimise stigma.