How pregnancy influences renal function in nephropathic type 1 diabetic women depends on their pre-conceptional creatinine clearance

Pregnancy in type 1 diabetic women with overt nephropathy can lead to a fur ther deterioration in renal function but it is not clear at what level of p re-conceptional GFR the risk for worsening of renal function begins to incr ease. Therefore we investigated the influence of pregnancy on renal functio n in 12 women (14 pregnancies) with preconceptional macroproteinuria and ne ar-normal creatinine clearance (range 37-93 ml/min/1.73m(2)), S-creatinine, creatinine clearance (CrCL), HbA1c and blood pressure (BP) were measured b efore conception, during each trimester (12(th) and 24(th) week of gestatio n and last week before delivery) and three and six months post-partum, In f ive diabetic women with six pregnancies (group A) there was a physiological increase in CrCl of 36% up until the 24(th) week of gestation; their pre-c onceptional mean CrCl was 80 (range 70-93) ml/min/1.73m(2). In seven women with eight pregnancies (group B) CrCl decreased by 16% during the first two trimesters; the mean CrCl before conception was 61 (37-73) ml/min/1.73m(2) . In the last week before delivery CrCl worsened transiently in three cases in group A and four in group B, due to pre-eclampsia. Three months post-pa rtum the mean CrCl in group A was 78 (70-91) ml/min/1.73m(2), approximately the same as before pregnancy, In group B the mean CrCl was 39 (22-68) ml/m in/1.73m(2) at this same time; this was 36% lower than the pre-conceptional clearance. Mean HbAlc in both groups were approximately the same, but mean BP tended to be higher during pregnancy in group B, especially in the week before delivery (p<0.05). We conclude that in a high percentage of nephrop athic diabetic women with significantly low CrCl before conception, renal f unction worsens during and after pregnancy Inadequate antihypertensive ther apy may contribute to this.