Rationale and Design of the FREQUENCY Study: The Fetal Cardiac Registry of Québec to Improve Resource Utilization in Fetal Cardiology

Abstract Objective Prenatal detection of congenital heart diseases (CHD) decreases morbidity and cost. To improve detections rates, most physicians refer pregnant women with high-risk pregnancies to fetal cardiologists even when there is no suspicion of CHD at the second trimester screening. This paper presents the rationale and detailed method of the Fetal Cardiac Registry of Quebec to Improve Resource Utilization in Fetal Cardiology (FREQUENCY) study. The overall objective is to assess the impact of second trimester ultrasound screening (U/S) and referral pattern in fetal cardiology on detection rates, health care costs, and resource utilization, as well as perinatal morbidity and mortality. Methods This multicentre retrospective population-based cohort study will link fetal echocardiography data from all centres performing fetal echocardiography in Quebec with administrative health care data. This data linking will allow the determination of a true denominator (all women in Quebec who underwent second trimester U/S) with complete follow-up of up to 2 years for offspring. This protocol meets Canadian Task Force Classification II-2. Results The study investigators have collected and cleaned fetal echocardiography data for 24 259 eligible pregnancies referred to fetal cardiology. These data will be matched to approximately 860 000 pregnancies between 2007 and 2015. Conclusion The results of the FREQUENCY study will shed light on the impact of the current prenatal CHD screening strategy in Canada.