We present 2 examples of previously apparently undescribed congenital anomalies that recurred in a subsequent pregnancy. In one case this was a multiple-congenital-anomalies syndrome of hydranencephaly with multinucleated neurons, hypoplastic kidneys, and syndactyly of the second and third toes. The second case involved atrioventricular valve thickening resulting in tricuspid insufficiency and mitral stenosis. These cases suggest that if after a complete autopsy the findings are unprecedented, then the recurrent risk in a subsequent pregnancy may be high. This hypothesis has not been tested prospectively.