Authors: El-Shahawy H. (MD), Ibrahim A. (MD), Hanafi S.(MD),Farag K

To investigate whether changing maternal position from left lateral to supine position in pregnant women between 36 and 40 weeks gestation, can affect umbilical and cerebral blood flow indices in low and high risk pregnancies. This study was a cross sectional study carried out at Ain Shams university maternity hospital on fifty pregnant women with singleton pregnancy between 36 and 40 weeks of gestation who attended the ultrasound special care unit of the fetus between December 2014 and August 2015 and were divided into two groups, Group A included 25 women with low risk pregnancy and Group B included 25 women with high risk pregnancy. The local medical ethics committee approved the study and oral informed consent was obtained from every patient involved in the study.This study included 2 groups of women: group A (low risk group) [n=25 women], and group B (high risk group) [n=25 women].   All indices were measured in the supine position then in the left lateral position and results were compared in the same group for proper correlation. In group A, our data demonstrated a statistically significant (p< 0.01) decrease in umbilical artery Systolic/Diastolic (S/D) (2.72±0.45 to 2.25±0.31), Pulsatility index (PI) (0.94±0.13 to 0.78±0.12) and Resistance index (RI) (0.63±0.06 to 0.55±0.06) ratio after changing maternal posture from left lateral to supine position respectively. Similarly there was a statistically significant (p< 0.01) decrease in middle cerebral artery S/D (4.84±1.39 to 3.77±0.98), PI (1.52±0.26 to 1.36±0.27) and RI (0.78±0.05 to 0.72±0.06) ratios too by using paired t-test. In group B, our data demonstrated a statistically significant (p< 0.01) decrease in umbilical artery S/D (2.52±0.33 to 2.23±0.25), PI (0.91±0.16 to 0.81±0.13) and RI (0.60±0.05 to 0.55±0.05) ratios but not V mean after changing maternal posture from left lateral to supine position. Similarly there was a statistically significant (p< 0.01) decrease in middle cerebral artery S/D (3.51±0.86to 3.04±0.68), PI (1.30±0.30 to 1.15±0.27) and RI (0.70±0.07 to 0.66±0.07) ratios but not V mean by using paired t-test.Left lateral position avoids partial obstruction of inferior vena cava (IVC) and aorta by the gravid uterus and ensures best blood supply to the uterus and placental circulation. Left lateral position is more appropriate to detect reactivity and for performing non stress test (NST) test in a shorter period compared with the supine position. By using this position fetal reactivity is more quickly observed and could decrease the need for prolonged monitoring, thus leading to a more time effective evaluation of patients at risk. Supine positioning of pregnant women during any kind of lengthy diagnostic or therapeutic intervention should be avoided.

 

Keywords

Left Lateral maternal position – Supine Position – Umbilical cord blood flow – Fetal cerebral blood flow

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The Effect of Changing Maternal Position from Left Lateral to Supine Position on Umbilical and Fetal Cerebral Blood Flow Indices