Prenatal genetic testing and analysis in the past was usually only offered when a particular fetal phenotype was noted or suspected, meaning that filtering and interpretation of genetic variants identified could be anchored in attempts to explain an existing health concern. Advanced genomic testing is now increasingly used in "low-risk" pregnancies, producing information on genotype adrift of the phenotypic data that is necessary to give it meaning, thus increasing the difficulty in predicting whether and how particular genetic variants might affect future development and health. A challenge to healthcare scientists, clinicians, and parents therefore is deciding what qualities prenatal genotypic variation should have in order to be constructed as a 'result.' At the same time, such tests are often re requested in order to make binary decisions about whether to continue a pregnancy or not. As a range of professional organizations develop guidelines on the use of advanced genomic testing during pregnancy, we highlight the particular difficulties of discovering ambiguous findings such as variants with uncertain clinical significance, susceptibility loci for neurodevelopmental problems and susceptibility to adult-onset diseases. We aim to foster international discussions about how decisions around disclosure are made and how uncertainty is communicated.