Correlates of syphilis seropositivity and risk for syphilis-associated adverse pregnancy outcomes among women attending antenatal care clinics in the Democratic Republic of Congo

Screening and treatment for syphilis among pregnant women is the primary means of prevention of congenital syphilis. Sentinel surveillance for syphilis can inform these prevention efforts. We reviewed antenatal syphilis screening results to assess trends and to identify correlates of seropositivity among women attending antenatal care clinics in the Democratic Republic of Congo during 2011. Syphilis seropositivity among the 17,669 women attending the antenatal care clinics during 2011 was 4.2% (range 0.4%-16.9%). Syphilis seropositivity was significantly higher among women attending rural clinics (5.0%) as compared to urban clinics (3.0%) and those tested in antenatal care clinics in the provinces of Equateur (7.6%) and Orientale (7.7%) as compared to other provinces (p<0.001). Based on the antenatal care syphilis seroprevalence and national pregnancy estimates, we estimate that approximately 128,591 pregnant women countrywide would have tested seropositive for syphilis during 2011. Over 85,000 adverse pregnancy outcomes would have resulted from these maternal infections, assuming prenatal syphilis diagnosis and treatment were not available. The prevalence of syphilis was highest in rural areas, but exceeded 1% in every area, indicating a need to assure screening and treatment throughout Democratic Republic of Congo. These sentinel surveillance estimates can be used to guide national congenital syphilis prevention efforts.