Stop the spread: predictors of inadequate syphilis treatment in pregnancy

To identify factors associated with inadequate or no syphilis treatment during pregnancy within an urban low-income safety-net hospital.

We conducted a retrospective case control study of pregnant patients diagnosed with new syphilis infections between July 2019 and July 2024 to determine predictors of inadequate or no treatment. Treatment was considered adequate if patients received appropriate doses of intramuscular benzathine penicillin G consistent with syphilis stage. Fisher's exact test and χ² test were performed for categorical variables. After adjusting for age, body mass index, substance use during pregnancy, diagnosis before 24 weeks and syphilis stage, a multivariable logistic regression was used to calculate adjusted OR (aOR) with a 95% CI. Statistical significance tests relied on a two-sided α=0.05.

A total of 150 pregnant patients were diagnosed with syphilis; approximately 36.7% (n=55) received no or inadequate treatment. Late latent and unknown syphilis stages were predictors of inadequate syphilis treatment with the following respective aORs: aOR 4.52; 95% CI 1.10 to 18.6 and aOR 7.64; 95% CI 2.19 to 26.7. Infection diagnosis before 24 weeks' gestation (aOR 0.18; 95% CI 0.07 to 0.42) was a significant predictor of adequate treatment. Partner treatment status was unknown or none for 89.3% of patients (n=134).

Patients diagnosed with syphilis stages that require multi-dose treatments are at higher risk for inadequate treatment. Efforts to promote early diagnosis and staging in this community are needed. Widespread neglect of partner treatment may be contributing to this epidemic.