Maternal autoimmune systemic connective tissue disease and vasculitis and electrocardiographic findings in the offspring.

Introduction: Maternal autoimmune systemic connective tissue diseases (CTDs) and their related antibodies have been associated with adverse fetal outcomes, including complete heart block. In this study, we assessed the association between maternal CTD or vasculitis and neonatal electrocardiographic (ECG) parameters.

Methods: Our study population was drawn from the Copenhagen Baby Heart Study (CBHS), a prospective, population-based cohort study open to all neonates born in the Copenhagen area. All CBHS neonates born to mothers with CTD or vasculitis were matched 1:3 to neonates born to mothers without these diseases on sex, gestational age, age and weight at time of examination, and maternal age at delivery. Maternal CTD and vasculitis diagnoses were validated through medical record review. Our primary analyses compared ECG parameters for exposed and unexposed neonates overall. Where numbers allowed, subanalyses were then conducted by specific CTD diagnoses and autoantibody types.

Results: Among 17,862 CBHS neonates with an available ECG, 40 neonates of mothers with CTDs or vasculitis (50 % males, median age 12 [interquartile range 8-16] days) were matched to unexposed neonates. Overall, no significant differences in heart rate, PR interval, QRS axis, QRS duration, QT/QTc interval, or R- or S-wave amplitudes were found when comparing exposed and unexposed neonates (all p > 0.05). Similarly, separate analyses of the 10 neonates with anti-Ro/SSA-positive mothers and their matched comparators revealed no significant between-group differences. However, neonates born to mothers with antiphospholipid syndrome (n = 15) had a significantly longer QRS duration (median 56 ms vs. 52 ms, p = 0.02) and corrected QT interval (median QTcBaz 430 ms vs. 414 ms, p = 0.01), compared with matched unexposed neonates.

Conclusion: In this population-based study, no significant overall differences in ECG parameters were found between neonates exposed to maternal CTD or vasculitis and unexposed neonates. However, neonates exposed to maternal antiphospholipid syndrome had significantly longer QRS- and QTc intervals than unexposed neonates. The potential clinical implications of these findings are unknown and, combined with the limitations of this study, warrant further investigation in larger cohorts.