Reinfection caused by gestational syphilis: A case report and systematic review of the literature

Objectives: To present a case of gestational syphilis (GS) caused by reinfection and conduct a systematic review of the literature regarding the frequency, diagnosis, treatment, and follow-up of reinfection. Materials and methods: A 21-year-old immigrant woman was hospitalized for preeclampsia and bacterial vaginosis. She reported being diagnosed and treated for GS in the first trimester, with a subsequent decrease in Venereal Disease Research Laboratory (VDRL) titers, followed by a new elevation detected at week 39. A diagnosis of syphilis reinfection was made, and she was treated again with benzathine penicillin. The newborn presented a positive VDRL test with a titer of 1:2, but without clinical signs or sequelae of Treponema pallidum infection. The infant was diagnosed with Congenital Syphilis (CS), and treated with intravenous crystalline penicillin G, with satisfactory outcomes. A systematic review of the literature was conducted from the inception of each database until November 2023 in Medline (PubMed), Embase, Scopus, Web of Science, and Lilacs. Case reports, case series, and cohorts of pregnant women with syphilis reinfection were selected. Two authors independently selected the studies and extracted the data. Study characteristics, population details, diagnostic features, GS treatment, and reinfection frequency were described. Descriptive analysis was performed. Results: A total of 208 potentially relevant titles were identified, of which 12 were reviewed in full text. Ultimately, six articles were included. In total, 85 women experienced syphilis reinfection during pregnancy (3.8%). The incidence of syphilis reinfection during pregnancy ranged from 1.5% to 7.3%. Diagnosis was predominantly made using non-treponemal tests (83.3%). Available information regarding the treatment of pregnant women with reinfection, follow-up, partner treatment, and perinatal outcomes was limited. Conclusions: Active and individualized monitoring of treated GS cases is crucial, as it enables the identification of reinfection and ensures the treatment of sexual partners to prevent recurrence. Prospective studies are needed to assess the magnitude of this problem, its perinatal consequences, and potential resistance to penicillin.