Congenital syphilis in neonates with nonreactive nontreponemal test results

Infants whose mothers had syphilis during pregnancy were studied to determine how often exposed newborns with normal physical examinations and nonreactive nontreponemal serologic tests had abnormal laboratory or radiographic studies.

Retrospective analysis of prospectively collected data from infants born to mothers with syphilis and had a normal examination and a nonreactive nontreponemal test. Some infants had IgM immunoblotting, PCR testing or rabbit infectivity testing (RIT) performed.

From 1984 to 2002, 115 infants had a nonreactive serum Venereal Disease Research Laboratory (VDRL)/rapid plasma reagin (RPR) test and a normal physical examination at birth. Among 87 infants born to mothers who had untreated syphilis, 4 had a positive serum IgM immunoblot or PCR test, but none had spirochetes recovered by RIT. Two infants had anemia, one had an elevated serum alanine aminotransferase concentration and one with Down's syndrome had direct hyperbilirubinemia. Among 14 infants born to mothers treated <4 weeks before delivery, none had abnormal laboratory or radiographic tests, although 1 of 11 had a reactive serum IgM immunoblot. Among 14 infants born to mothers treated ⩾4 weeks before delivery, none had abnormal laboratory or radiographic tests.

Newborns with normal physical examination and nonreactive nontreponemal test results are unlikely to have abnormalities detected on conventional laboratory and radiographic testing.