Monitoring Syphilis During Pregnancy
Abigail Zuger, MD reviewing Rac MWF et al. Clin Infect Dis 2015 Mar 1.
Maternal titers after treatment did not predict congenital syphilis.
We consider a patient with syphilis to be treated adequately when the nontreponemal titers fall fourfold or more within 6 to 24 months, depending on stage of disease and patient's HIV status. However, this standard was derived from studies in nonpregnant adults. How (or if) this standard should apply to pregnant women, in whom the overriding concern is preventing congenital syphilis in the neonate, is unclear.
Researchers at a single Texas hospital retrospectively reviewed the serology of 166 pregnant women in whom syphilis was diagnosed at 18 weeks' gestation or later and who were treated with CDC-approved regimens before delivery. Patients were seen between 1981 and 2011. Slightly more than half the women had early disease (primary, secondary, or early latent). Only one was HIV positive.
Titers declined after treatment along typical patterns: Titers in patients with primary and secondary disease fell more rapidly than in those with later-stage disease, and older age predicted relatively slow titer response. Although only 63 of the women (38%) achieved fourfold decreases in titer by delivery, the 27 cases of congenital syphilis identified were divided equally between neonates of faster and slower responders. None of the women required retreatment for presumed treatment failure.