Abstract Objective: To measure development of the psychological distress that pregnant women undergo following the detection of structural anomalies by ultrasonography. Design: A prospective, longitudinal observational study at department of fetal medicine, Oslo University Hospital, Rikshospitalet (OUS-R) Population: 76 pregnant women were included after referral to department of fetal medicine due to abnormal findings at an ordinary ultrasonography. The inclusion period was from May 2006 to February 2009. Methods: Psychological distress was measured by a self-report questionnaire, the Impact of Event Scale-22 (IES-22), following the ultrasonography at the department of fetal medicine and three weeks later, on average. Psychological distress is divided into three dimensions; intrusion, avoidance and hyper arousal. The fetal anomalies were categorized by severity and ambiguity the first time and by change in severity the second time. Results: There was an overall reduction in psychological distress during three weeks (P<0.001). Change in severity, gestational age at inclusion, parity and age of the mother had no significant influence on the development of psychological distress as measured by the three subscales of IES-22 at the second time of assessment. Previous spontaneous abortion was significantly associated with a lesser reduction in the subscales avoidance (P=0.010) and hyper arousal (P=0.05). Conclusions: We measured a lower level of psychological distress three weeks after detection of a structural anomaly at ultrasonography examination, compared to assessment at the time of detection of fetal anomaly. A previous spontaneous abortion predicted a lesser decrease in distress. Because of a lack of background information, these findings demand further investigation before any conclusions can be made.