Anti-SSA/Ro positivity and congenital heart block: obstetric and foetal outcome in a cohort of anti-SSA/Ro positive pregnant patients with and without autoimmune diseases

Objective Neonatal lupus (NL) is an acquired disease caused by the transplacental passage of anti-SSA/Ro antibodies. The rate of congenital heart block (CHB), its most serious manifestation, ranges from 1 to 5%. The aim of this study was to retrospectively assess the prevalence of CHB in anti-SSA/Ro positive pregnant women with or without systemic autoimmune diseases from 2010 to 2020. Methods Patients underwent monthly visit and a shared follow-up programme of weekly (16th-24th week) foetal heart rate assessment by obstetric ultrasound. Results 322 pregnancies in 258 anti-SSA/Ro patients were included; 314 were followed from the beginning of pregnancy because of the known presence of anti-SSA/Ro autoantibodies and 1 case of CHB occurred in an anti-SSA/Ro+ asymptomatic subject (0.3%). In the same period, 8 additional patients were referred to our clinics after in utero CHB diagnosis and subsequent discovery of anti-SSA/Ro without a disease diagnosis. Globally, 9 cases of congenital CHB (2.8%) occurred: 7 complete, 1 II-III degree and 1 first degree CHB. Anti-SSB/ La positivity was associated with a higher risk of CHB (7.8% vs. 1.2%; p=0.0071). No differences in maternal or foetal outcomes were found in comparison with a large cohort of unselected pregnancies except for caesarian section. Hydroxychloroquine (HCQ) was used in 58.3% pregnancies, with a different prevalence according with maternal diagnosis. Conclusion Our data suggest that anti-SSA/Ro positive patents with a defined systemic autoimmune disease undergoing a strict follow-up since positive pregnancy test display a low risk of pregnancy complications, including but not limited to NL.