Effects of pregnancy on the onset and progression of diabetic nephropathy and of diabetic nephropathy on pregnancy outcomes.

Controversy exists regarding the effect of pregnancy on the development and course of diabetic nephropathy. This study followed 43 pregnant women with previous diabetes mellitus, 32 without nephropathy (Group I) and 11 with nephropathy (Group II). Urinary albumin excretion (UAE), serum creatinine (Cr) and creatinine clearance (CCr) in the pre-pregnancy (Pre-P), first trimester (1T), third trimester (3T) and 1 year postpartum (PP) were evaluated. In both groups there were an increase in 3T compared to Pre-P of CCr (137 vs. 98 ml/min and 110 vs. 81 ml/min, p=0.0001, respectively) and UAE (7.78 vs. 3.15 mg/24 h and 592 vs. 119 mg/24 h, p=0.0001, respectively). Increase of Cr in the PP compared to 1T in Group II (0.88 vs. 0.70 mg/dL, p=0.031) was observed. There were no difference in UAE, CCr and Cr in the PP when compared to pre-P as well variance over time between groups. Group II showed higher prevalence of chronic hypertension (72.7 vs. 21.9%, p=0.004), preeclampsia (63.6 vs. 6.3%, p=0.0003) and lower gestational age at birth (36 vs. 38 weeks, p=0.003). We conclude that pregnancy was not associated with development and progression of diabetic nephropathy in women with or without mild renal dysfunction. The presence of diabetic nephropathy was associated with increased risk of perinatal complications.