The metabolic disturbances of the balance acid-base3, asphyxiation perinatal4, 6 and fetal7 death. The prevalence of this entity varies from 15% during pregnancy up to 33% at the time of the parto8-10. The high frequency of lace circular has been associated with excessive length of the umbilical cord, polyhydramnios, small fetuses and vertice9 presentations, 11. At least in cases in which there is the diagnosis There is no clinical evidence of fetal distress, is indication of monitoring with fetal monitoring during labor, and with the emergence of variable decelerations or understanding of lace – for some authors – data is indication of cesarea5, 6. The search routine, either by media clinicians or lace circular enclosure, can contribute to decrease morbidity and mortality perinatal12.

There are different diagnostic methods to detect circular cord; clinical methods include understanding of the cuello10 and the vibroacustica5 stimulation and methods of Cabinet, among the ultrasonido10. Diagnostic ultrasound real time, 3.5 capacity is evaluated in the present study Mhz. MATERIAL and methods studied 114 patients who were admitted to the old maternity Bolognesi (current Virgin del Pilar clinic) in Trujillo, Peru, with pregnancy at term and in labor at active phase, without obstetric complications. Was made to all ultrasound obstetric (use) to his income, for the identification of lace circular; subsequently entered the service of hospitalization for management and surveillance of the labor. At the time of vaginal delivery or cesarean section, it was verified the presence or absence of circular cord in each of the patients who participated in the study.