39: Progression of ultrasound findings of fetal syphilis following maternal treatment


      To evaluate ultrasound findings of fetal syphilis and describe their progression after maternal treatment.

      Study Design

      This is a retrospective cohort study from September 1984 to June 2011 of women diagnosed with syphilis after 18 weeks of gestation who had an ultrasound to evaluate fetal syphilis. Women not treated prior to delivery were excluded. If the ultrasound showed evidence of fetal syphilis, it was repeated weekly until resolution or delivery. Patient demographics, ultrasound findings, stage of syphilis, delivery and infant outcomes were recorded. Standard statistical analyses were performed.


      235 women met inclusion criteria and 73 (30%) had evidence of fetal syphilis on initial ultrasound. Abnormalities were more common in early stage disease (58%). These included hepatosplenomegaly (HSM) (81%), placentomegaly (21%), ascites (11%), polyhydramnios (11%) and abnormal MCA dopplers (32%). Polyhydramnios was the first abnormality to resolve and did so by 2.8 +/− 0.3 weeks after treatment. This was followed by resolution of ascites, placentomegaly, MCA doppler abnormalities and finally HSM. Infant outcomes were available for 142 deliveries. Overall,32(23%) were diagnosed with congenital syphilis. Congenital syphilis was more common when antenatal ultrasound abnormalities were present (49% vs.15%, p<0.001). However, 9(56%) of those infants were born < 4 weeks after maternal treatment. In infants who had an abnormal ultrasound but born with congenital syphilis >4 weeks after maternal treatment, HSM was the only finding still present on exam at delivery (28%).


      This is the first study to describe the course of fetal syphilis after antepartum treatment. Sonographic signs of fetal syphilis confer a higher risk of congenital syphilis at delivery for all maternal stages. Hepatosplenomegaly develops early and resolves last after antepartum treatment. Further studies are needed to clarify whether findings at delivery are due to active infection or cure with resolving abnormalities.