(P6) RELATIONSHIP BETWEEN NEONATAL NONTREPONEMAL TITERS AND CONGENITAL SYPHILIS TREATMENT PATTERNS IN NEONATES BORN TO PEOPLE WITH ADEQUATELY TREATED SYPHILIS DURING PREGNANCY

Background:
Consistent application of treatment recommendations for asymptomatic neonates with low/equivocal nontreponemal (NT) syphilis titers born to people with adequately treated syphilis is complicated given the poor testing performance of these tests to diagnose pregnant persons with reinfection and neonates with congenital syphilis (CS). This study aims to describe clinician practice patterns for these neonates in a well-characterized cohort of exposed pregnant person-neonate dyads.

Methods:
This was a prospective cohort study of all pregnant patients with adequately treated syphilis and their neonates with deliveries between 5/2023 and 2/2024 at a large academic center in Texas. All syphilis-related variables including laboratory results and treatment history for each dyad were recorded.

Results:
Of 37 pregnant patients, 20 (54.1%) were adequately treated prior to delivery. Based on the Centers for Disease Control and Prevention’s CS Clinical Scenarios, of those 20, 3 neonates (15%) met scenario 1 (confirmed proven or highly probable), 1 (5%) met scenario 2 (possible), and 2 (10%) delivered elsewhere. As such, 14 (70%) met criteria for scenario 3 or 4 (less likely or unlikely). Of neonates with less likely or unlikely CS, 11 (78.6%) received one dose of intramuscular (IM) benzathine penicillin G (BPG) and 3 (21.4%) received no treatment. Of neonates who received BPG, 4 (36.6%) had titers that were ≥1:4, while all who received no treatment had titers of ≤1:1. Two (14.3%) of the pregnant people did not have a 4-fold decrease in titers prior to delivery and both neonates in these pregnancies received one dose of IM BPG.

Conclusion:
Clinician treatment patterns for neonates at low risk for CS vary. Data regarding optimal treatment is lacking given the challenge of longitudinal neonatal follow-up required to confirm absence of syphilis infection. Further efforts to address these gaps are critical given the escalating rates of CS.