Early alterations of renal function in insulin-dependent diabetic pregnancies and their importance in predicting pre-eclamptic toxaemia.

: Renal function, blood pressure and glycaemic control were assessed during gestation in 23 non-azotaemic insulin-dependent diabetic women. Pre-eclamptic toxaemia (PET) developed in nine cases, and was predicted by higher levels of albuminuria excretion, mean blood pressure and serum urate early in pregnancy, as well as by the primigravid state. Mean blood pressure, serum creatinine and urate remained stable in the first trimester and rose thereafter in women who developed PET. Levels of mean blood pressure were significantly higher in the second (p less than 0.005) and third (p less than 0.0001) trimesters, serum urate was higher in the first, second (p less than 0.04) and third (p less than 0.0001) trimesters, as was AER (p range less than 0.02-0.0001), and serum creatinine levels were higher in the third trimester (p less than 0.02) in comparison to those women who did not develop PET. Glycaemic control was similar in both groups. In addition, physiological alterations in creatinine clearance, and in serum levels of creatinine and urate were attenuated in cases uncomplicated by PET. Insulin-dependent diabetic pregnancies are characterized by disturbances of renal function early in pregnancy which may be predictive of PET, particularly in primigravidae and/or when accompanied by increases in mean blood pressure.