Proteinuria: a risk factor for pregnancy-related renal function decline in primary glomerular disease?

Pregnancy may be followed by a postpartum acceleration of renal function loss in patients with renal disease. We retrospectively analyzed the effects of pregnancy on progressive renal function decline, and the risk factors for an acceleration, in a group of 19 renal disease patients with 30 pregnancies and a group of 31 patients who did not become pregnant after onset of glomerular disease. The rate of renal function loss was calculated for each patient by linear regression on reciprocal serum creatinine values over 11 years' follow-up. Multiple regression analysis showed that both pregnancy (P = 0.03) and initial proteinuria (P = 0.005) were independently related with the rate of renal function loss. Such a relation could not be observed with histologic diagnosis, and initial age, renal function, blood pressure, and serum albumin. Further analysis showed that 10 of 30 pregnancies are followed by a predefined acceleration of renal function loss. These pregnancies were preceded and complicated by a higher proteinuria (4.1 v 1.7 g/d, P < 0.005; and 3.6 v 2.1 g/d, P < 0.05, respectively) compared with the other 20 pregnancies that are not followed by such an acceleration. In conclusion, patients with primary glomerular disease complicated by substantial proteinuria are at risk for acceleration of renal function decline after pregnancy.