How late can AV block develop in children of mothers with SSA antibodies?

 Makadia L, et al. Am J Perinatology Reports 2023;13:e29-e34.

Pubmed search: 2 groups of studies

Group 1 - Prospective studies (Prenatal)

Group 2 - Retrospective studies.

Group 1: 10 studies, reporting 1248 cases.

Group 2: 9 studies.

Take home points:

From the Introduction:

Maternal autoantibodies cross placenta in 2nd trimester and cause inflammation that leads to AV block. Therefore, screening should start at 16 weeks gestation.

Maternal autoantibodies clear infant's blood by 6 months of age. Therefore, usual onset of AV block is within first year.

From a Swedish Congenital Heart Block Study Group - 1949 - 2009. 190 cases were reported. However, the values in the abstract or in Table 2 of the Makadia et al. report do not correlate. Nevertheless, there were 9 patients diagnosed in the age 4 mo - 18 yrs and 4 patients diagnosed in the age > 18 yrs. (Need to reconcile the numbers with original publication). Bergman G et al. Acta Paediatr 2014;103:275-81.