effects of pregnancy: induced hypertension on umbilical artery blood flow in the third trirnester

ABSTRACT

Doppler ultrasound of umbilical vessels is a method of evaluating fetoplacental blood flow which is very important in high risk pregnancies and can predict both the duration of maternal hospitalization and fetal mortality rates in IUGR. Pregnancy induced hypertension is one of the most important causes of high-risk pregnancies. In this study, the rate of blood flow through umbilical artery as well as its degree of resistance were measured, using Doppler ultrasound in the patients with pregnancy induced hypertension. This is a cross-sectional study which was carried out on 35 pregnant women with pregnancy induced hypertension in the year of 2004. All of the cases were studied during their third trimester. 61 pregnant women in their third trimester were selected as the control group. They all had normal blood pressure. Doppler ultrasound of umbilical artery was performed for both the case and the control groups. Then, Peak Systolic Velocity [PSV], End Diastolic Velocity [EDV] and mean velocity were measured, based of which Resistive Index [RI], Pulsatility Index [PI] and Systolic to Diastolic ratio [S/D ratio] were calculated. Finally the statistical analysis was performed on the obtained recorded data, using SPSS software. The results indicate a measure of 0.77 for RI; 1.39 for PT and 4.88 for S/D ratio in the case group while in the control group, such measurements were calculated as 0.64; 1.08 and 2.97, respectively. As a whole, the comparison of the mean values of the mentioned indices revealed a significant difference between the two groups [P<0.01]. The case group were significantly rated higher in terms of the above mentioned indices. In patients with pregnancy induced hypertension without having other risk factors [such as diabetes, mellitus and IUGR], Doppler ultrasound should be used for evaluating the degree of fetoplacental blood flow in order to decrease the risk of pregnancy complications