Measuring the Utility of Prenatal Exome Sequencing Using the Clinician‐Reported Genetic Testing Utility InDEx for Prenatal Care: A Retrospective Multicentre Study

ABSTRACT Objective To assess the diagnostic and clinical utility of prenatal exome sequencing (ES) in a cohort of pregnancies using the Clinician‐reported Genetic testing Utility InDEx for Prenatal Care (C‐GUIDE Prenatal). Methods Cases that met criteria for prenatal ES in Ontario, Canada were identified in 5 clinics. Clinicians assessed the utility of ES using C‐GUIDE Prenatal, a clinician‐reported measure of how genetic testing informs pregnancy and neonatal management. Case characteristics were summarized descriptively. C‐GUIDE Prenatal total scores were calculated and regressed against clinically important variables using generalised estimating equations. Results Among 115 cases, the diagnostic yield was 41.7%. The mean C‐GUIDE Prenatal score was 9.48 (SD 11.51). Compared with negative results, informative positive results were associated with an increase in C‐GUIDE Prenatal score of 17.6 ( p < 0.001). Compared to meeting one criterion for ES, meeting ≥ 3 criteria was associated with an increase in C‐GUIDE Prenatal score of 3.8 ( p < 0.05). Compared with pregnancies that were not ongoing at result disclosure, ongoing pregnancy was associated with an increase in the C‐GUIDE Prenatal score of 2.8 ( p < 0.001). Conclusion Findings address a knowledge gap in the clinical value evidence base that informs policy and funding decision‐making for prenatal genetic testing.