Disruption to action potential propagation can affect the AV and SA nodes which are part of the conduction system of the heart.Fetal susceptibility and environmental factors could also play a role in pathogenesis since not all infants develop congenital heart block even when exposed to antibodies. Clinical manifestations
Neonatal lupus can present with several signs and symptoms. The most common manifestations involve the heart and skin. Problems involving the liver, gallbladder, brain, and blood can be seen but are usually transient. Heart
Cardiac manifestations present more commonly in utero, but can also present after birth. The most common complications are varying degrees of heart block and endocardial fibroelastosis. A large percentage of infants diagnosed with isolated congenital heart block are associated to neonatal lupus. Heart block occurs when there is dysfunction in the conduction system, preventing impulses from traveling from the atria to the ventricles. Heart block can initially present with bradycardia in the prenatal period, usually around the second trimester. Infants with lower grades of heart block can progress to higher grades, but they can also present with rapid onset of complete heart block. Endocardial fibroelastosis is considered a type of cardiomyopathy that occurs in response to heart cell injury and can be seen with or without conduction system dysfunction.Common complications

First degree heart block
Second degree heart block
Third degree heart block (Complete heart block)
Endocardial fibroelastosisOther complications seen with neonatal lupus

Patent ductus arteriosus
Patent foramen ovale
Pulmonic stenosis
Pulmonary valvular dysplasia
Fusion of chordae tendineae of the tricuspid valve
Ostium secundum type atrial septal defects

Skin
A rash can be seen upon delivery.
Screening is usually performed when there is a higher likelihood for neonatal lupus such as individuals who are more likely to have antibodies due to autoimmune diseases or individuals who have had prior pregnancies complicated with neonatal lupus. If a fetus develops heart block, screening for maternal antibodies can be considered. Monitoring for heart block can be done using a fetal echocardiogram. Management
Infants with neonatal lupus are managed with supportive care. This means treating or monitoring the symptoms that can occur from this disease. For example, avoiding sunlight so that the infants rash wont worsen. Many of the manifestations are transient, but once complete heart block occurs, it is irreversible. Heart block can be managed in utero if diagnosed during pregnancy. Infants born to mothers with anti-Ro/SSA and anti-La/SSB should have an ECG performed to check for heart abnormalities if none were seen while in the uterus. In utero
Fetal heart block treatment varies based on the degree. First degree heart block is usually treated with glucocorticoids, but it can also reverse on its own. As of right now, treatment guidelines for first-degree heart block is controversial due to lack of evidence. Second degree heart block commonly progresses to complete heart block. Second degree heart block can also reverse on its own. Treatment includes fluorinated glucocorticoids and immunoglobulin therapy. Third degree heart block is irreversible, and many treatments have been attempted without success. Management is mainly expectant. Early delivery should be avoided unless other complications arise.