Frequencies of vertebral patterns for fetuses with malformations of different organ systems. Vertebral patterns are indicated with R, LS, TL, TL_LS, CT, CT_LS, CT_TL, CT_TL_LS, see Fig. 2 for an explanation. Malformations are indicated for the different organ systems: MS Muscular System, NS Nervous System, UG Urogenital System, CV Cardiovascular System, BP Bronchopulmonary System, LD Limb Defects, VBW Ventral Body Wall Defects, DS Digestive System, SK Skeletal Malformations, CF Craniofacial Malformations, No Mal No Malformations. The group with no malformations has the highest incidence of regular patterns and the groups with skeletal and craniofacial malformations has the lowest incidence of regular patterns