THE CLINICAL-SIGNIFICANCE OF ANTENATAL DETECTION OF DISCORDANT UMBILICAL ARTERIES

Objective: To evaluate the clinical significance of the antenatally de tected discordant umbilical arteries (UAs). Methods: Women with single ton gestations undergoing sonographic evaluations were examined for th e presence of discordant UAs. Transverse and longitudinal diameters as well as the area of both UAs were measured. Doppler now velocity wave forms were recorded from both arteries. Macroscopic and microscopic ex amination of the umbilical cord was performed after delivery and the a rea of each artery was measured. Mann-Whitney LI test and Spearman ran k correlation were used for statistical purposes. Results: Data are pr esented as median (range). Discordance between UAs was found in 14 of 1012 women who underwent sonographic examinations. The vessel diameter s and areas differed significantly between the discordant UAs (diamete r 2.9 [1-4.3] versus 4.5 [3.8-6.5] mm, P < .001; area 6.6 [0.78-14.5] versus 16.25 [11.33-33.16] mm(2), P < .001). A significant difference between UA size was confirmed after delivery (area 1.68 [0.9-3.06] ver sus 4.17 [1.12-13.8] mm(2), P < .005). The difference in the area of t he UAs in utero and at microscopic examination correlated significantl y (r = .94, P < .05). In all cases, the resistance index was higher in the smaller artery than in the larger artery (0.71 [0.59-0.8] versus 0.6 [0.48-0.75] P < .01). Abnormal insertion of the umbilical cord or an abnormality of the placenta was present in eight cases. Perinatal d eath occurred only in a trisomic infant born al 24 weeks' gestation. C onclusion: The clinical significance of discordant UAs is that newborn s are generally in good condition at birth and placental anomalies are common in this group of parturients. Abnormal Doppler velocimetry of the smaller UA should be taken with caution, because it does not seem to be associated with poor perinatal outcome. (C) 1998 by The American College of Obstetricians and Gynecologists.