Influence of Prenatal Counseling in Invasive Testing

It is well established that screening for Down syndrome should be offered in the first trimester to each pregnant woman. The most common screening method is nowadays the first trimester combined test which consists of a Bayesian analysis of the a priori risk of maternal age for Down's syndrome, and the posterior risk combining serum biomarkers such as beta fraction of the human chorionic gonadotropin (β-hCG), pregnancy-associated plasma protein-A (PAPP-A), and nuchal translucency measurement. Women at high risk for trisomy 21 or 18 using this combined test are eligible for chorionic villous sampling or amniocentesis for a final diagnosis. In recent years there has been a huge advance in prenatal screening for Down's syndrome with the advent of cell free DNA testing with higher sensitivity and specificity than the combined test, in which a positive result must be also confirmed by an invasive diagnostic procedure. But as the range of options broadens, also the need for health education to allow women to have an adequately informed decision process on which prenatal test better suits their needs. In multicultural cities, this has become especially important to integrate patient's values and expectations to an evidence-based decision regarding prenatal testing. There is high-quality evidence demonstrating that aversion to risk of fetal loss related to an invasive test may come from incomplete information, shaping the attitude towards which test to choose from the mother's point of view. And the disbelief that by taking cfDNA testing the risk of miscarriage would be reduced. Many information is available about preferences and attitudes in prenatal testing from Northern European studies, but scarce information is available from Southern Europe, where the amniocentesis rate in the nineties was as high as 40% of the urban pregnant population. The investigators hypothesize that when enough information is given before the initial screening, women will overcome aversion to