Neonatal lupus syndrome. Association with complete congenital atrioventricular block

Neonatal lupus erythematosus (NLE) is characterized by persistent congenital complete heart block, often without any other structural heart defects. Lupus-like dermatitis is seen transiently, more rarely hepatitis and thrombocytopenia occurs. Recent investigations have shown a close relation between NLE and maternal anti-Ro/La antibodies. These antibodies seem responsible for the destruction of the bundle of His and the AV node in the foetus. Total AV block is seen in 1:15.-22,000 of liveborn children, 70-90% of them are caused by NLE. It is difficult to identify the pregnancies at risk since at delivery most of the mothers (up to 66%) are without symptoms. If the mother has anti-Ro/La antibodies the risk for having a child with NLE is probably less than 5%. However, new investigations have shown that mothers who in addition have anti-DNA antibodies have significantly lower risk of bearing a child with NLE. In most cases foetal complete AV block is found accidentally during pregnancy. Slow foetal heart rate with the demonstration of AV dissociation should not, unless the foetus shows sign of incompensation, lead to acute delivery, but pregnancy should be monitored carefully by serial echocardiography. More than half of the children with congenital heart block need pacemaker therapy shortly after birth. The other children should be followed closely for signs of incompensation and may need pacemaker therapy later on.