Dilatation of the left renal vein in preeclampsia

Our purpose was to compare the morphological changes in renal veins during normal pregnancy and pregnancy involving preeclampsia.

We used ultrasonography to measure maximum diameters of the right and left renal veins, and the diameter of the left renal vein where it crosses the abdominal aorta in normal pregnancy and preeclampsia.

In women with normal pregnancy, the maximum diameter of the left renal vein was 5.5 +/- 1.9 mm in the 1st trimester, 5.8 +/- 1.6 mm in the 2nd trimester, and 6.4 +/- 1.4 mm in the 3rd trimester. The diameter of the left renal vein where it crosses the abdominal aorta was 3.3 +/- 1.1 mm in the 1st trimester, 4.1 +/- 1.3 mm in the 2nd trimester, and 4.0 +/- 0.9 mm in the 3rd trimester. In contrast, the maximum diameter of the left renal vein in women that had preeclampsia with onset in the 2nd trimester was 9.8 +/- 2.4 mm and that in women whose preeclampsia began in the 3rd trimester was 8.7 +/- 1.6 mm. The diameter of the left renal vein in preeclampsia was significantly larger than that in normal pregnancy (P < 0.05). There were no significant differences between normal pregnancy and preeclampsia in the maximum diameter of the right renal vein or that of the left renal vein where it crosses the abdominal aorta.

In preeclamptic women, a dilatation of the left renal vein was observed. This suggests that the relative constriction and congestion of the left renal vein takes part in the pathophysiology of preeclampsia. Measurement of the diameter of the left renal vein would provide a simple, cost-effective tool for the diagnosis of preeclampsia.