Increasing Syphilis Diagnoses Among Females Giving Birth in US Hospitals, 2010-2014

National trends in syphilis rates among females delivering newborns are not well characterized. We assessed 2010-2014 trends in syphilis diagnoses documented on discharge records and associated factors among females who have given birth in US hospitals.

We calculated quarterly trends in syphilis rates (per 100,000 deliveries) by using International Classification of Diseases, Ninth Revision, Clinical Modification codes on delivery discharge records from the National Inpatient Sample. Changes in trends were determined by using Joinpoint software. We estimated relative risks (RR) to assess the association of syphilis diagnoses with race/ethnicity, age, insurance status, household income, and census region.

Overall, estimated syphilis rates decreased during 2010-2012 at 1.0% per quarter (P < 0.001) and increased afterward at 1.8% (P < 0.001). The syphilis rate increase was statistically significant across all sociodemographic groups and all US regions, with substantial increases identified among whites (35.2% per quarter; P < 0.001) and Medicaid recipients (15.1%; P < 0.001). In 2014, the risk of syphilis diagnosis was greater among blacks (RR, 13.02; 95% confidence interval [CI], 9.46-17.92) or Hispanics (RR, 4.53; 95% CI, 3.19-6.42), compared with whites; Medicaid recipients (RR, 4.63; 95% CI, 3.38-6.33) or uninsured persons (RR, 2.84; 95% CI, 1.74-4.63), compared with privately insured patients; females with the lowest household income (RR, 5.32; 95% CI, 3.55-7.97), compared with the highest income; and females in the South (RR, 2.42; 95% CI, 1.66-3.53), compared with the West.

Increasing syphilis rates among pregnant females of all backgrounds reinforce the importance of prenatal screening and treatment.