Glomerular filtration rate in pregnancy: a study in normal subjects and in patients with hypertension, preeclampsia and diabetes.

We have studied renal function during pregnancy using plasma clearance of iohexol to determine the glomerular filtration rate (GFR). In normal pregnancy, GFR was elevated by 40% throughout pregnancy and during the first week post partum, and fell to levels similar to those in non-pregnant women within 1 month. The development of GFR in diabetic pregnant women and in women with gestational hypertension was similar to that recorded in normal pregnancy. In subjects with preeclampsia the rise in GFR observed in normal pregnancy was absent, and no change in GFR was recorded after delivery. We conclude that the development of proteinuria and fluid retention typical of preeclampsia is paralleled by a deterioration of GFR.