Anti-Ro Congenital Heart Block Risk Pregnancy — ESENeph MCQ

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ModeratePregnancy & RenalAnti-Ro Congenital Heart Block Risk PregnancyESENeph

A 32-year-old woman at 10 weeks' gestation with lupus nephritis in remission on azathioprine 100 mg daily presents with a positive anti-Ro (SSA) antibody. Her rheumatologist is concerned about neonatal lupus. What fetal complication is she at highest risk for?

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Correct answer: D — Congenital complete heart block

Anti-Ro (SSA) and anti-La (SSB) antibodies cross the placenta and can cause neonatal lupus syndrome. The most serious manifestation is congenital complete heart block (CCHB), which occurs in ~2% of anti-Ro-positive pregnancies (risk increases to 15-20% if a previous child was affected). CCHB results from antibody-mediated inflammation and fibrosis of the fetal cardiac conduction system, typically developing between 16-24 weeks' gestation. Monitoring includes serial fetal echocardiography from 16 weeks (weekly/biweekly during the high-risk window). Dexamethasone (which crosses the placenta) may be used for incomplete heart block, though evidence is limited. Most neonatal lupus manifestations (rash, cytopenias) are transient, but CCHB is irreversible and may require neonatal pacing.

Reference: Buyon et al 2003 – Neonatal Lupus and Anti-Ro; EULAR 2017 – SLE Pregnancy Recommendations