Infants of diabetic mothers have three to four times the incidence of congenital malformations than that in the general population. These anomalies include defects of the neural tube, heart, urogenital system, skeleton and alimentary tract, and the caudal regression syndrome. The anomalies are considered to result from the maternal metabolic derangements. The mechanism has been suggested to involve a diminished turnover of phosphoinositide or arachidonic acid, or an excess of free oxygen radicals. As most of the anomalies in infants of diabetic mothers occur in the first few weeks of pregnancy, strict glycemic control beginning before conception appears mandated.