True knot of the umbilical cord: a report of 13 cases.

True knots of the umbilical cord are complications that can result in obstetric disasters, including fetal asphyxia and eventual fetal death. This study reports on 13 patients with a true knot of the umbilical cord in a delivery population of 967 deliveries during a 1-year period. In this group, there was one second-trimester fetal demise, four cases of fetal distress during labor necessitating cesarean delivery, and eight cases with a true knot found incidentally at delivery. No abnormal sequelae were found for the 12 viable newborns. True knots of the umbilical cord can be incidental findings; however, a tightened knot is reported to be associated with a fourfold increased risk of fetal death. Prenatal fetal surveillance, including targeted sonographic examination and Doppler studies, may identify true knots of the umbilical cord. Identification of high-risk patients and clinical expertise in the management of these patients have not been established.