For clinicians

Anti-Ro/SSA antibodies and neonatal lupus

anti-Ro, anti-SSA, SSA/SSB, congenital heart block, neonatal lupus

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Bottom lineBottom line: anti-Ro/SSA (and anti-La/SSB) can cause neonatal lupus, including congenital heart block (CHB). Baseline CHB risk is ~1-2%, rising to ~15-20% after a previously affected child. Hydroxychloroquine reduces recurrence; serial fetal echocardiography in the vulnerable window enables early detection. Most anti-Ro pregnancies are uncomplicated.

By domain

What anti-Ro/SSA antibodies mean ●●●○moderate evidencestrong

Anti-Ro/SSA antibodies can cross the placenta and affect the fetal conduction system and skin. Presence matters more than the underlying diagnosis for CHB risk.^{[1, 3]}

Heart block risk (baseline and recurrence) ●●●○moderate evidencestrong

Baseline CHB risk ~1-2%; recurrence ~15-20% after a prior affected child. Once complete, CHB is usually irreversible, which is why prevention and early detection matter.^{[1, 2]}

Lowering the risk (hydroxychloroquine) ●●●○moderate evidenceconditional

Hydroxychloroquine (started by ~10 weeks) reduced recurrent advanced CHB to ~7.4% in the PATCH study versus a historical ~18%. Continue throughout.^[2]

Fetal heart monitoring ●●○○low evidenceconditional

Serial fetal echocardiography through the vulnerable window (approx weeks 16-26), often weekly to fortnightly; escalate if a conduction abnormality is detected.^{[2, 3]}

If a heart problem is found ●○○○very low evidenceconditional

Emerging or incomplete block may prompt consideration of fluorinated steroids (dexamethasone); evidence is limited and management is individualised with fetal cardiology.^[3]

Neonatal lupus after birth ●●●○moderate evidenceconditional

Cutaneous neonatal lupus (photosensitive rash) is usually transient; less commonly hepatic or haematologic involvement. Non-cardiac manifestations typically resolve as maternal antibodies clear.^[3]

Key points

Point	Evidence
Hydroxychloroquine reduces CHB recurrence and is recommended in anti-Ro-positive pregnancies.^[2]	●●●○moderate evidenceconditional
The majority of anti-Ro pregnancies are uncomplicated; surveillance enables early detection in the minority.^[1]	●●●○moderate evidencestrong

Key numbers

Brucato 2001 (verified, primary text): prevalence of congenital complete heart block was 2% (2/100) in prospectively followed anti-Ro/SSA-positive women with known connective tissue disease. Both cases were detected at 20 and 22 weeks' gestation.^[1]
Recurrence risk ~15-20% after a prior affected child.^[2]
PATCH: advanced CHB recurrence ~7.4% on hydroxychloroquine started by 10 weeks.^[2]

References

Brucato A, et al. Risk of congenital complete heart block in newborns of mothers with anti-Ro/SSA antibodies. Arthritis Rheum. 2001;44(8):1832-1835. https://pubmed.ncbi.nlm.nih.gov/11508435/
Izmirly P, et al. Hydroxychloroquine to Prevent Recurrent Congenital Heart Block in Fetuses of Anti-SSA/Ro-Positive Mothers (PATCH). J Am Coll Cardiol. 2020;76(3):292-302. https://www.jacc.org/doi/10.1016/j.jacc.2020.05.045
Tarter L, Bermas BL. Expert Perspective: Lupus and Pregnancy. Arthritis Rheumatol. 2024;76(3):321-331. https://acrjournals.onlinelibrary.wiley.com/doi/10.1002/art.42756