Pregnancy Ultrasound Detecting Soft Markers – the Challenge of Communicating Risk Figures

Abstract: This thesis focuses on expectant parents’ experiences and needs when soft makers are detected at mid-trimester ultrasound, resulting in an unexpected assessment of risk for fetal anomalies. The thesis also describes the prevalence of ultrasonographic fetal soft markers and the incidence of Down syndrome in a low-risk population of 10,535 pregnant women with a total of 10,710 fetuses, as well as the risk of invasive prenatal diagnostics in conjunction with the detection of soft markers. Finally, the thesis aims to explore the value of a web-based patient decision aid (DA) in facilitating informed decision making regarding routine fetal screening for anomalies and the fathers’ role in decision making regarding prenatal screening.A prospective observational study was conducted between 2008–2011 to investigate the prevalence of ultrasonographic fetal soft markers at second trimester screening. During this time period, 12 women and 17 men were interviewed about their experience when soft markers were detected. Based on the results of these interviews, a web-based decision aid (DA) to enhance expectant parents’ decision-making concerning fetal screening was developed and a trial initiated to test its utility. Interviews were conducted with 17 women who received access to the DA, 11 who had chosen to use the DA and six who had not used it. All interview studies were analysed using systematic text condensation (STC) developed by Malterud.Soft markers were detected in 5.9% of the fetuses at mid-trimester ultrasound, whereof 5.1% were isolated. All soft markers showed a positive likelihood ratio (LR+) for DS; however, the association was only statistically significant for the collapsed category ‘any marker’ (isolated, multiple or combined with anomaly), not for isolated markers. An almost 24-fold increase of invasive diagnostic testing was shown in all women, including those with a low estimated risk for aneuploidy, i.e. < 1/200 (paper III).The results from interviews showed that the finding of soft markers created much anxiety and indicated that both women and men lacked awareness of the potential of the ultrasound examination (papers I and II). The results also showed that the men were actively engaged in decision making not only by supporting their partners, but also considered their own values and needs regarding these issues (paper II). It was also evident that women wanted their partners to be engaged in decisions regarding fetal diagnostics (papers I and IV).The web-based patient DA was able to initiate a process of conscious decision making in pregnant women, as a result of their interaction with the tool. The DA allowed for clarification of women’s thoughts and priorities and helped them to understand the significance of the screening result and providing a basis for making informed decisions regarding fetal screening (paper IV).

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