Congenital heart block can develop in the fetus during pregnancy in a woman with SSA and SSB autoantibodies. International studies report a mortality rate of 25-30%. Through our clinical and molecular studies, we have established a surveillance program in which we observe less than 4% mortality, as well as a significantly increased time after birth to pacemaker need in the child. However, in the majority of SSA/SSB positive pregnancies, no heart block develops - and almost half of all blocks develop in pregnancies where the woman is not known to carry SSA/SSB antibodies. The aim of this project is to identify biomarkers to identify the high-risk pregnancies and surveillance methodology so that the program can be made available to all at-risk pregnancies. We will use a world-unique biobank of samples collected over a 15-year period to identify clinically useful markers using proteomic methodology. Screening methods to identify at-risk pregnancies in large groups will be developed using immunological techniques. Reducing mortality from a disease by a quarter is a breakthrough that we now want to make available to the wider population and the world.