ABSTRACT
To investigate whether normal pregnancy has a significant effect on intrarenal venous blood flow and to assess whether the physiological maternal pyelocaliectasis causes a measurable change in venous impedance indices in pregnant women. Cross sectional comparative study. Radiology Departments, KRL Hospital Islamabad and Combined Military Hospital Lahore from Jan 2010 to Jul 2010. A total of 50 normal pregnant women in their second and third trimester and 50 controls, i.e. normal non-pregnant married healthy women of childbearing age were included in the study. Confounding variables were controlled by excluding subjects having recent or previous renal calculi, pathological renal conditions or congenital renal anomalies or generalized disorders affecting haemodynamics ruled out by history, clinical examination and ultrasound examination in both pregnant and non-pregnant women. After grading the degree of hydronephrosis, venous impedance index was obtained from the interlobar veins. Overall the collecting system dilatation was present in 60% of 50 right kidneys and 42% of 50 left kidneys in the pregnant women. The venous impedance indices were significantly lower in 50 pregnant women than the values in non-pregnant subjects [p< 0.001 for the right and the left kidney]. The overall difference in venous impedance indices between right and left kidneys was not significant in pregnant women [p = 0.11]. There was an inverse correlation between the grade of pelvicalyceal dilatation and the venous impedance indices in both kidneys in 50 pregnant women. Normal pregnancy causes dilatation of the pelvicalyceal system and significant reduction in renal venous impedance index values in second and third trimesters. Therefore one should be careful in interpretation of an abnormally reduced venous impedance index and hydronephrosis as a sign of pathological ureteral obstruction in pregnant women