Cost and clinical utility of repeated syphilis screening in the third trimester in a high-risk population

We sought to determine the clinical utility and cost of repeating syphilis testing in the third trimester of pregnancy in a high-risk urban population.

A retrospective cohort analysis was performed for patients delivering from January 1993 through December 2009 with at least 1 venereal disease research laboratory (VDRL) test sent during pregnancy. Chart review was performed for patients with confirmed syphilis to determine the temporal relationship of syphilis diagnosis to the pregnancy. For patients who seroconverted during pregnancy (no antecedent history or treatment for syphilis), newborn charts were reviewed. The costs of treating seropositive neonates and the costs of implementing additional third-trimester syphilis screening were then compared.

In the 17-year cohort, 58,569 deliveries were available for analysis. In all, 113 new cases of syphilis occurred (192.9/100,000 deliveries). There were 17 detected seroconversions; 10 were not rescreened in the third trimester and tested positive at delivery. These 10 patients may have benefitted from implementing uniform VDRL testing at 28-32 weeks' gestation. All newborns were asymptomatic with a negative workup and received empiric penicillin therapy. Based on 2011 hospital charges, the cost of evaluating and treating a neonate for syphilis is $11,079. Implementing an additional VDRL screen at 28-32 weeks' gestation for each pregnant patient during the 17 years studied would cost $1,991,346. An 18-fold increase in syphilis prevalence (3500/100,000 [3.5%] deliveries) would be required for the cost of implementation of universal early third-trimester screening to be equal to the potential health care charges saved by detecting maternal seroconversion and obviating the need for neonatal therapy.

In this high-risk population, additional syphilis screening in the third trimester is costly and is not clinically helpful in detecting maternal seroconversion.