Effects of Hypoplastic Fetal Umbilical Artery on Doppler Findings For Common Iliac Arteries

Background: The umbilical cord contains two arteries and one vein. Normally, the diameters of umbilical arteries are close in size, but this may vary, as one umbilical artery may be considerably smaller or more hypoplastic than the other. Objectives: This study aimed to investigate the effect of hypoplastic umbilical arteries on Doppler ultrasonography (US) findings for the common iliac arteries (CIAs), such as the pulsatility index (PI) and resistive index (RI) values, and to investigate the associations between hypoplastic fetal umbilical arteries and placental, umbilical cord, and fetal pathologies. Patients and Methods: Doppler US was performed on 165 pregnant women between 18 and 22 weeks of gestation, and again between 27 and 37 weeks of gestation. The umbilical artery diameters and both CIA flow parameters (PI and RI) were measured during these visits. The presence of a diameter difference of greater than 25% (95th percentile) between the two umbilical arteries was accepted as a hypoplastic umbilical artery. Results: Eleven of the 165 patients (6.7%) demonstrated a hypoplastic umbilical artery. Second-trimester US showed median dominant and non-dominant CIA PI values of 1.43 and 1.60 (P = 0.062), respectively, and median dominant and non-dominant CIA RI values of 0.80 and 0.85 (P < 0.001), respectively, in the hypoplastic umbilical artery group. Third-trimester US showed median dominant and non-dominant CIA PI values of 1.24 and 1.66 (P = 0.062), respectively, and median dominant and non-dominant CIA RI values of 0.73 and 0.82 (P = 0.002), respectively, in the hypoplastic umbilical artery group. We did not observe an association between hypoplastic umbilical arteries and placental, umbilical cord, or fetal pathologies. Conclusion: Our study revealed that the hypoplastic umbilical artery group’s non-dominant CIA had higher RI values than the contralateral dominant CIA.