Syphilis in the 'unbooked' pregnant woman.

To determine the prevalence of syphilis in the 'unbooked' pregnant woman attending King Edward VIII Hospital, Durban, mothers who had no previous history or record of antenatal care were studied over a 3-month period. One hundred and fourteen mothers were recruited, 35 (30.7%) of whom had reactive syphilis serology. None had clinical evidence of primary or secondary syphilis. Clinical evidence of congenital syphilis was found in 4 of the 35 (11.5%) babies born to mothers with reactive syphilis serology. While the fluorescent treponemal antibody absorption (FTA-ABS) IgG test was positive in umbilical cord and neonatal venous blood of all 35 babies, the FTA-ABS IgM test was negative in all specimens, including the sera from the 4 babies with clinical signs of syphilis. The FTA-ABS IgM test is therefore of little value for the laboratory confirmation of congenital syphilis. It also has limitations when it comes to screening asymptomatic neonates born to mothers with reactive syphilis serology.