Anti-Ro/La Antibodies and Pregnancy

Ro (anti-Ro) and La (anti-La) antinuclear autoantibodies are associated with autoimmune congenital heart block (ACHB), which is an acquired immune-mediated condition associated with placental transfer of these maternal autoantibodies. It occurs in 1–2% of anti-Ro/La-positive pregnancies and has a recurrence rate of about 15–20%. It develops in the foetal heart in the absence of anatomical abnormalities that would otherwise account for heart block. ACHB is typically diagnosed in utero, and less frequently at birth or within the neonatal period. Anti-Ro/anti-La-mediated damage of foetal conduction pathways in the heart causes inflammation and fibrosis, leading to blockage of signal conduction at the atrioventricular (AV) node. The majority of ACHB infants present with third-degree heart block/complete AV block. Some infants develop other severe cardiac complications, such as endocardial fibroelastosis (EFE) or valvular insufficiency, even in the absence of cardiac block. Managing such pregnancies affected by anti-Ro/La antibodies, including asymptomatic carriers, neonatal lupus, and ACHB, is challenging. Relevant screening and pre-conception counselling, along with prevention and treatment, are all important aspects of its management.