Detailed Anomaly Scan

theultrasoundsuite.ie/maternity/detailed-anomaly-scan.html. Screening for Fetal Chromosomal Abnormalities. Babycentre Anomaly Scan (18 weeks - 24 weeks). This scan is probably the most important diagnostic scan that takes place in a pregnancy. The fetus is the correct size to have all the organs assessed so that the sonographer can see whether you baby has an obvious defect such as spina bifida or a cleft palate.