ABSTRACT
A comparison was made of ultrasonographic diagnosis of fetal nuchal encirclement by the umbilical cord versus the gold standard in pregnant, women at labor. 114 pregnant women at labor were studied. On admission to the labor and delivery room, each patient underwent an abdominal ultrasonographic evaluation for the identification of nuchal encirclement by the umbilical cord and the diagnosis by ultrasound was compared versus direct visualization of the umbilical cord at the moment of delivery or cesarean section (gold standard). Of the 114 patients studied, the prevalence of nuchal cord diagnosed by ultrasound was 20.1%. The diagnostic test had a sensitivity of 80% (CI 95%: 72.66-87.34), specificity of 96% (CI 95%:92.91-99.09), and positive and negative predictive values of 87% and 94% respectively. The accuracy of the test was 92%. Analysis of the discordances by the McNemar's test was not significative between obstetric ultrasound and the gold standard (p = 0.7236). The likelihood ratios were 20 and 0.20 for a positive and a negative results respectively. The ultrasonographic study during labor for diagnosis of nuchal encirclement by the umbilical cord had a high specificity (96%), and this advantage permit it to be utilized like screening test for the identification of high risk pregnancies with nuchal cord.
