This study evaluates the impact of the various outcomes of pES (definitive diagnosis, probable diagnosis and IF) on clinical decision making and on parental psychological wellbeing, compared between different analysis strategies to investigate the clinical utility, defined as the balance between potential harms and benefits.

Foetal anomalies as detected on prenatal ultrasound are present in 2-3% of pregnancies. The diagnosis of a genetic syndrome as the underlying cause often has significant consequences for the prognosis and therefore also a significant impact on parental reproductive decision making. In addition to chromosomal testing, prenatal exome sequencing (pES) is increasingly being offered. Although prenatal diagnostic rates are promising, no studies report on the actual implementation of pES in routine care and thus several important knowledge gaps remain regarding clinical utility (the balance between potential harms and benefits) and the preferred analysis strategy (broad versus targeted analysis). A broad analysis has a possible higher diagnostic yield, but it is unknown whether the increased chance of finding an uncertain diagnosis and Incidental Findings outweighs this benefit when it comes to clinical decision making and parental psychological wellbeing. The central aim of this study is to address the knowledge gaps raised above, and increase clinical utility by using the obtained data to improve analysis strategies and to potentially identify new genes.

Inclusion Criteria:

• At least one fetal anomaly detected in the current pregnancy, irrespective of gestational age;
• Pregnancy ongoing;
• Mother at least 18 years old and providing consent for pES;
• If father is available: father at least 18 years old and providing consent for pES.

Exclusion Criteria:

There are no exclusion criteria.

Pregnant women with one or more ultrasound findings during the current pregnancy who consent to pES, and their partner.