“…At present, studies addressing facial clefts 8 , isolated 9 and associated 10 heart malformations, limb reduction deficiencies 11 , neural tube defects 12 and abdominal wall defects 13 The detection rate varied widely between registries, from 62% to 97% for neural tube defects 12 from 11% to 48% for congenital heart disease 9,10 , from 0% to 64% for limb reduction deficiences 11 from 0% to 75% for cleft lip palate 8 , from 0% to 100% for omphalocele and from 18% to 100% for gastroschisis 13 , and from 38% to 72% for gastrointestinal anomalies (Hausler et al, unpublished data) despite the fact that the registries participating in this study used the same methodology. Variations in detection rate may result from differences in operator skill, equipment used, or the gestation at which examinations are performed.…”