The Utility of Screening Fetal Echocardiograms Following Normal Level II Ultrasounds in Fetuses with Maternal Congenital Heart Disease

INTRODUCTION: Fetal echocardiograms (F-echo) are recommended in all pregnancies when maternal congenital heart disease (CHD) is present, even if there was a prior level II ultrasound (LII-US) that was normal. The goal of this study was to evaluate if any diagnosis of a critical CHD was missed in a fetus with maternal CHD who had a normal LII-US. METHODS: A retrospective chart review of all F-echoes where the indication was maternal CHD between 1/1/2015 to 12/31/2022 was performed. Fetuses were included if they had a LII-US that was read as normal and had an F-echo. Critical CHD was defined as CHD requiring catheterization or surgical intervention < 1 month of age. RESULTS: A total of 296 F-echoes on fetuses with maternal CHD were evaluated, of which 175 met inclusion criteria. LII-US was performed at 19.8 ± 2.9 weeks gestational age and F-echo was performed at 24.2 ± 2.8 weeks gestational age. No patient with a normal LII-US had a diagnosis of a critical CHD by F-echo (negative predictive value = 100%). Evaluating those patients that had a negative LII-US, ten patients were diagnosed with non-critical CHD postnatally (negative predictive value = 94.3%). F-echo correctly diagnosed two of the ten missed LII-US CHD. CONCLUSIONS: Critical CHD was not missed with a normal LII-US in this at risk population. F-echo also missed the majority of CHD when a LII-US was read as normal. A cost-benefit analysis of screening F-echo in fetuses with maternal CHD should be conducted if a normal LII-US has been performed.