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Abstract

Background: Oligohydramnios, defined by reduced amniotic fluid volume, is a significant indicator of placental insufficiency and fetal compromise. Amniotic fluid plays a critical role in cushioning the fetus, supporting pulmonary development, and facilitating fetal movements. Doppler ultrasound of key fetal vessels, such as the umbilical artery (UA) and middle cerebral artery (MCA), provides valuable insights into fetal hemodynamics in compromised pregnancies. Evaluating these indices can help clinicians identify fetuses at risk and guide timely intervention.
Objective: To compare the Doppler indices of the umbilical artery and middle cerebral artery between pregnant women diagnosed with oligohydramnios and those with normal amniotic fluid levels.
Methods: This cross-sectional observational study was conducted at Jinnah Hospital Lahore and included 73 pregnant women between 18 and 40 years of age. Participants were divided into two groups: oligohydramnios (n=29) and normal amniotic fluid (n=44). Amniotic fluid levels were assessed using the amniotic fluid index (AFI) and single deepest pocket (SDP) methods. Doppler ultrasonography was used to measure peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), resistance index (RI), and systolic/diastolic (S/D) ratios for both UA and MCA. Statistical analyses were performed using SPSS version 24, with a significance level set at p<0.05.
Results: The mean umbilical artery PSV was significantly lower in the oligohydramnios group (34.53 ± 17.60 cm/s) compared to the normal fluid group (52.85 ± 16.39 cm/s). Similarly, the MCA PSV was 36.54 ± 15.05 cm/s in oligohydramnios and 57.66 ± 19.71 cm/s in the normal group. MCA EDV was 10.62 ± 6.44 cm/s in oligohydramnios versus 21.39 ± 11.65 cm/s in controls. Although MCA PI was higher in oligohydramnios (1.40 ± 0.21) compared to normal (1.22 ± 0.35), this was not statistically significant (p=0.2668). No significant differences were observed in most RI and PI values.
Conclusion: Oligohydramnios is associated with marked reductions in fetal blood flow velocities, especially in the umbilical and middle cerebral arteries, reflecting compromised fetal circulation. Doppler evaluation of these vessels offers a reliable, non-invasive method to monitor fetal well-being and anticipate adverse outcomes in high-risk pregnancies.