Umbilical cords often become encircled around portions of the fetus, usually the neck. The incidence ranges from 21% in one loop to 0.2% in three loops. In the present study, we assessed the practice of severing the cord, which was encircled once around the neck of the fetus, after delivery of the anterior shoulder and prior to extraction of the body. This was a prospective, randomized, controlled study. The study and the control groups included 30 women each. Cord around the neck was diagnosed during labor by ultrasound. It was cut intentionally in the study group and left intact in the control group. Demographic data were obtained. The course of labor was assessed. Neonatal outcomes measured were cord pH, Apgar scores at 5 minutes, and need for resuscitation. Length of maternal and neonatal hospitalization was determined. No differences were found between the study and the control group before, during, and after labor regarding perinatal variables such as meconium-stained amniotic fluid, fetal heart rate patterns, Apgar scores at 5 minutes, and umbilical cord pH after delivery (7.29 +/- 0.07 [SD] in the study group and 7.32 +/- 0.06 [SD] in the controls; p=0.1). Single nuchal encirclement by the umbilical cord during labor, after delivery of the anterior shoulder, can be severed or left intact. We could not detect any adverse perinatal outcome in such deliveries.