Decision making and attitudes towards invasive prenatal diagnosis in the early second trimester

To investigate the impact of the a priori attitude, nondirective counselling and targeted second trimester ultrasound examination on the decision process concerning invasive prenatal diagnosis in the second trimester.

A prospective study including 696 high-risk pregnancies at 15 to 18 weeks' gestation, performed from 2005-2007. Attitudes towards invasive prenatal testing were explored before and after genetic counselling and targeted ultrasound examination in a tertiary referral centre.

Initially, 311 (44.7%) women intended to have an invasive testing (group 1), 150 women (21.5%) were against an invasive procedure (group 2), and 235 women (33.8%) wanted to make their final decision depending on the sonographic result (group 3). The total rate of amniocentesis was 87.1%, 5.3% and 13.6%, respectively. Overall, the a priori decision was sparsely influenced by the ultrasound examination. Only 12.9% (40/311) and 5.3% (8/150) of the primarily determined women (group 1, 2) changed their opinion. However, in the initially undecided group, 86.7% declined an amniocentesis after a normal ultrasound scan.

The referral indication and the a priori opinion are the strongest influencing factors with regard to invasive testing and the ultrasound scan has a low impact in those preselected patients. However, ultrasound has an important reassuring aspect in women willing to use ultrasound as assistance in the process of decision making.