Researchers have found that pregnant patients with low anti–Ro antibody titers may be at minimal or no risk of fetal atrioventricular block, according to a press release from the American College of Rheumatology (ACR). Anti–Ro antibodies react with the Ro52 and Ro60 proteins and are often associated with autoimmune diseases such as lupus, Sjögren’s syndrome, and rheumatoid arthritis. The current standard of care for surveillance of the condition during pregnancy involves weekly or biweekly fetal echocardiograms; however, the test is only capable of detection during a brief window of time. In the ongoing STOP BLOQ study—data from which was presented by Cuneo et al at ACR Convergence 2023—researchers are examining prospective data from 483 pregnant patients to determine whether anti–Ro antibody levels correlate with the risk of fetal atrioventricular block. Patients involved in the study completed 17 to 26 gestational weeks of the monitoring period, were risk-stratified based on high and low anti–Ro60 and anti–Ro52 antibody titers, and monitored fetal heart rhythms and rates thrice daily. The researchers found that the patients who had titers of less than 1,000 units/mL were at low risk of developing fetal atrioventricular block. Among the 37% of patients who had low titers, none of them developed the condition. Conversely, 22% (n = 10/45) of the patients who had high titers had fetal atrioventricular block. When the patients detected fetal heart rhythms that were abnormal, they were referred by pediatric cardiologists to undergo surveillance with echocardiograms. The researchers hope that their new findings will inspire the development of novel home-monitoring devices to help differentiate normal and abnormal heart rhythms. They concluded that pregnant patients with higher anti–Ro antibody titers may benefit from ambulatory fetal heart rhythm monitoring to detect and treat the condition before it becomes irreversible.