Abstract 18375: Improving Rate of Prenatal Diagnosis of Critical Congenital Heart Disease Despite the Covid19 Pandemic: A Canadian Multiprovincial Study

Abstract

Background Restriction to travel, reallocation of health resources and physical distancing during the COVID19 pandemic caused extraordinary health system strain, requiring limited tertiary referral acceptance. The overall impact of public health measures during COVID19 on diagnosis of congenital heart disease (CHD) has not been explored. We sought to determine the rate, timing of diagnosis and pregnancy outcomes of critical CHD prior to and during the COVID era. Methods: Cases of CHD with due date/birth date from 1 Jan 2016 to 1 Mar 2022 that required or were anticipated to require neonatal intervention were identified from surgical and referring centres in Ontario and Alberta. Pregnancies were categorized as reaching 18 weeks GA before (pre-COVID) or after 1 March 2020 (COVID). Outcomes included timing of diagnosis (pre/postnatal), GA at prenatal diagnosis, and pregnancy outcome. Data are presented as mean, 95% CI or median (IQR); rank-sum comparison of continuous variables or Chi 2 comparison of proportions were used. Results: Prenatal diagnosis occurred in 1240/1823 (68% (65.8, 70.1)) of cases of critical CHD overall, with a pre-COVID rate of 867/1305 - 66% (64, 69) and COVID rate of 373/518 - 72% (68, 76), p=0.02. During COVID, earlier median GA at obstetric ultrasound (median GA: pre-COVID 20.1 (19.1, 22), COVID 19.9 (19.1,21.3), p=0.025) and diagnosis of CHD (median GA: pre-COVID 21.7 (20.3, 24.3), COVID 21.3 (20,23.3), p=0.006) occurred. Prenatal diagnosis before 22 weeks GA (pre-COVID 449/851, 52.3% vs COVID 219/371, 59%; p=0.043) and termination were more common during COVID (pre-COVID 28% (25,31), COVID 35% (30,40) p=0.015). Conclusion The rate of prenatal diagnosis of critical CHD continued to improve during the COVID pandemic in two of Canada’s largest provinces. Unexpectedly, obstetric ultrasounds occurred earlier, leading to earlier prenatal diagnosis of CHD. These findings may have implications for referral practices in the post-COVID era.