Perinatologist Corner - C.E.U/C.M.E. Modules
Syphilis in Pregnancy
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9. Congenital Syphilis
Case Scenario 4
D. S. is a 30 y/o G2P1, who had a negative RPR on her NOB labs at 15 weeks, has just delivered. The lab reports a positive RPR on her newborn's cord blood. The infant is well and has a normal physical exam. How should you manage this situation?
Congenital Syphilis
As stressed above, maternal serologic testing, and appropriate maternal treatment, remain the best preventive strategy for congenital syphilis. Nevertheless, all infants born to women with positive serology, treated or untreated, should be examined for evidence of infection. Jaundice, hepatosplenomegaly, rhinitis, rash, pseudoparalysis of an extremity, or radiologic evidence of periostitis or pneumonitis, strongly suggest neonatal disease. Such infants should have serologic studies performed on themselves and their mothers, and be treated as detailed below.
Serologic testing of maternal blood at the time of delivery is superior to infant testing because low maternal titers or late pregnancy maternal infections may result in false negative results in the infant. Conversely, transfer of maternal antibodies, even in adequately treated mothers, may result in false positives without actual vertical transmission. Umbilical cord blood testing is not recommended because of possible contamination with maternal blood, and because Wharton's jelly itself has been reported to be a cause of a false positive reaction with non-treponemal antibody testing. Treatment decisions need to be made on the basis of maternal history and treatment. Was the mother treated? Was she treated adequately? Was she treated with a non-penicillin regimen? Was she treated <4 weeks before delivery? Has she had a fourfold decrease in titer after treatment? Does the infant have clinical signs (see above)? A comparison of maternal and infant non-treponemal test titers is very helpful for guiding therapy. No currently available IgM treponemal test is considered reliable, so a VDRL or RPR on infant serum is the appropriate test to order.