Behavioral and socioeconomic factors create considerable obstacles to the elimination of congenital syphilis. A clear understanding of maternal risk factors is important to define interventions in every community.
The goal of this study was to investigate maternal risk factors for congenital syphilis.
We conducted a case-control and descriptive analysis of 3 groups of live born infants and their mothers consisting of: group I (cases of congenital syphilis), group II (neonates without congenital syphilis whose mothers had been adequately treated for syphilis), and group III (random sample of newborn infants whose mothers have not had syphilis). Data were prospectively collected from personal interview and antenatal records.
In the case-control study, including groups I and III, the maternal characteristics independently associated with congenital syphilis in the logistic regression were monthly per capita income under US $30 (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.1–7.4), single status (OR, 2.8; 95% CI, 1.1–7.8), and less than 6 prenatal visits (OR, 3.2; 95% CI, 1.3–8.1). Comparison between groups I and II (only mothers who have had syphilis) showed a strong protective association of prenatal care with congenital syphilis (OR, 0.05; 95% CI, 0.00–0.39). Additional analysis identified 2 separate profiles of maternal characteristics, one consisting of low socioeconomic status and the other of risk behaviors. Some women who had syphilis before or during pregnancy received adequate prenatal care and delivered infants without congenital syphilis. Most of these women had high-risk behaviors but they were, in general, less poor, older, and more educated than mothers of infants with congenital syphilis.
Risk behaviors and low socioeconomic characteristics constituted 2 separate maternal profiles associated with congenital syphilis. Socioeconomic risk factors interfered more with prenatal care. To become more effective, the strategies for prevention of congenital syphilis should be targeted to each maternal profile.
A case-control study in Porto Alegre, RS, Brazil, found two distinct profiles of characteristics in mothers of infants with congenital syphilis, one constituted by socioeconomic risk factors and the other constituted by behavioral risk factors.
*Department of Pediatrics, Pontifícia Universidade Católica do Rio Grande do Sul–PUCRS School of Medicine, Porto Alegre, RS, Brazil; the †Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, UK; and the ‡Department of Primary Care, Federal Foundation School of Medicine from Porto Alegre–FFFCMPA, Porto Alegre, RS, Brazil
Correspondence: Eleonor G. Lago, MD, 6690/715, CEP 90610-000 Porto Alegre, RS, Brazil. E-mail: firstname.lastname@example.org
Received for publication May 1, 2003,
revised August 25, 2003, and accepted September 4, 2003.