[Aplasia of the umbilical artery].

A study was undertaken at St-François d'Assise Hospital, Quebec City, to determine the incidence of single umbilical artery. During a two-year period the umbilical cord was examined in 4138 consecutive deliveries. Thirty-three cases of aplasia of an umbilical artery were found, an incidence of 0.79%, which is almost identical to that reported in previous studies. Five of the 33 newborn infants with this vascular anomaly had other congenital malformations; this incidence of associated malformations is 10 times higher than that found in a control series. In studying the weight of the infants in relation to the period of gestation, it was found that many of the 33 infants with aplasia of the umbilical artery had a lower weight at birth than normal infants. The possibility that the absence of one umbilical artery might be responsible for intrauterine malnutrition is advanced by the authors.