A pregnant woman may experience an increase in kidney and ureter size. The glomerular filtration rate (GFR) commonly increases by 50%, returning to normal around 20 weeks postpartum.[13] Plasma sodium does not change because this is offset by the increase in GFR. There is decreased blood urea nitrogen (BUN) and creatinine and glucosuria (due to saturated tubular reabsorption) may be seen.