Effect of oligohydramnios versus gestational hypertension on umbilical artery velocimetry

Objective: This study aimed to examine the hemodynamic changes in the umbilical artery among third-trimester pregnant women with oligohydramnios, gestational hypertension, and both conditions. Materials and Methods: A case-control study was conducted over nine months, enrolling 88 women in their third trimester. Participants were categorized into four groups: (1) normal, (2) oligohydramnios, (3) gestational hypertension, and (4) oligohydramnios with gestational hypertension. Doppler ultrasound was used to assess umbilical artery resistive index (UA RI), pulsatility index (UA PI), and systolic/diastolic ratio (SD ratio). Data were analyzed using independent sample t-tests, with p-values ≤ 0.05 considered statistically significant. Results: Women with gestational hypertension had significantly higher UA RI (0.63 vs. 0.58, p = 0.013), UA PI (0.88 vs. 0.80, p < 0.001), and SD ratio (2.91 vs. 2.28, p < 0.001) compared to women without hypertension. Women with oligohydramnios had lower UA RI (0.57 vs. 0.62, p = 0.025) but higher UA PI (0.77 vs. 0.86, p < 0.001) and SD ratio (2.34 vs. 2.68, p < 0.001) compared to women without. Among women with both conditions, UA PI (0.89 vs. 0.82, p = 0.002) and SD ratio (2.93 vs. 2.47, p < 0.001) were significantly elevated. Conclusion: Gestational hypertension is associated with increased UA RI, UA PI, and SD ratio, indicating higher vascular resistance. Oligohydramnios is characterized by lower UA RI but higher UA PI and SD ratio.