BACKGROUND: Fetal screening for Down syndrome by an ultrasound examination, including measurement of fetal nuchal translucency, at 12 to14 weeks' gestation is presently being evaluated in a Swedish randomized controlled trial. Women at high risk were offered an amniocentesis to obtain a definite diagnosis. The aim of this study was to explore women's reactions and responses to information about being at high risk after the scan, with a special focus on reactions to a false positive test. METHOD: Interviews were conducted with 24 women within 1 week after the scan, in midpregnancy, and 2 months after the birth. The interviews were analyzed qualitatively. Down syndrome was confirmed in 4 women, who chose to terminate the pregnancy. The remaining 20 women had a false positive test. RESULTS: For the majority, the risk information caused strong reactions of anxiety and worries about the future. A typical way for women to cope was to "withhold" the pregnancy, to take a "timeout," and try to live as if they were not pregnant any longer. Some weeks later, when the women received normal results from the chromosome analysis, they resumed being pregnant. Six women ages more than 35 years who had a risk score lower than their age-related risk did not express similarly strong reactions. Two months after the birth of a healthy baby, most stated they would undergo the same procedure in a subsequent pregnancy. One woman still suffered from the experience when interviewed at 2 months after the birth, and another said she regretted participating in the fetal screening program. CONCLUSIONS: A false positive test of fetal screening for Down syndrome by ultrasound examination may cause strong reactions of anxiety and even rejection of the pregnancy. The prevalence of such reactions and possible long-term effects need further investigation.