Deviation from the usual pattern of embryologic development produces an anomaly. In the vast majority of instances the etiologic factor responsible for the initiation of different developmental patterns cannot be determined. Nevertheless, several factors have been identified as having a direct relationship to the appearance of congenital deformities. Maternal viral infections, particularly rubella in the first 2 months of pregnancy, have been shown by several authors to be associated with a high incidence of anomalies. In experimental animals, the administration of substances such as steroids or estrogens has been shown to affect developmental patterns. The effect of an exogenous chemical stimulus upon the development of congenital anomalies has been strikingly demonstrated by the large number of deformities associated with the ingestion of thalidomide by women between the fourth and ninth weeks of pregnancy. Likewise, diets deficient in vitamins A and B have been found essential to the production of anomalies in rats. X-ray irradiation delivered during the prenatal period, particularly during the first trimester, should be avoided if at all possible because of the increased incidence of anomalies associated with its use.
KeywordsUreteropelvic Junction Ureteral Catheter Ureteral Orifice Wolffian Duct Calculus Formation
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