Characteristics of mothers of live infants with congenital syphilis in Florida, 1987-1989.

The incidence of congenital syphilis in Florida increased sixfold from 1985 through 1989, and more than 80% of the cases occurred in metropolitan areas of southern Florida. To characterize the population of pregnant women in Florida at high risk of delivering an infant with congenital syphilis, the authors conducted a case-control study using birth certificates. Birth certificates were obtained for 256 of the 344 live infants reported as having congenital syphilis from 1987 through 1989 (74%); the 246 of these infants born in hospitals were matched for hospital and week of birth with an equal number of controls. In conditional multiple logistic regression, the following maternal characteristics were independent risk factors for congenital syphilis: young age, black race, single marital status, absence of a father's name on the birth certificate, previous pregnancy, substance abuse, and lack of prenatal care. Although the national origin of the mother was not a significant risk factor, the infants of black mothers born in the United States were at greater risk than the infants of black mothers born outside the United States. Mothers who had < or = 3 prenatal visits had an increased risk of delivering an infant with congenital syphilis as compared with mothers who had > 3 visits. This study suggests that targeted outreach efforts are necessary to control congenital syphilis and provides guidance for public health intervention activities.