Risk Factors of Wang et al for Congenital Syphilis in China

Exclusions: HIV-positive

An infant was considered to have congenital syphilis if the TPPA (Treponema pallidum particle agglutination assay) was positive at 18 months. In noninfected infants any passively acquired IgG antibodies are undetectable by 15 months. This is beyond the period for transplacental transfer of IgG antibodies, suggesting enteroabsorption from breast milk.

If an infant tested negative for both RPR and TPPA at any time was diagnosed as negative for congenital syphilis.

Factors associated with congenital syphilis in multivariate analysis:

(1) diagnosis of maternal syphilis > 36 weeks gestational age

(2) high titer of anti-treponemal antibodies (RPR, TPPA) in the mother

Additional factors from univariate analysis:

(1) mother a migrant worker with lack of prenatal care

(2) current syphilis in the father