Having said that, if it is truly just a 12 millimeter ventricular septal defect (VSD), there are a couple of things to know. First, this should not cause any problems
in utero, so following it with repeated ultrasonographic studies does not do anything to help your baby. It should not lead to any problems prior to delivery. Second, a 12 mm VSD is a large defect, whether it is in utero or post-natal; it is most assuredly not small.