Table 3.

Renal-Associated Changes During Pregnancy

Covariate	Pregnancy-Associated Changes
Serum creatinine	Decreases between 16%-23% in compared to prepregnancy levels
Renal osmolality	Decreases by ≈10 mOsm of water compared to prepregnancy levels
Blood urea nitrogen concentrations	Decreases by ≈10 mg/dL compared to prepregnancy levels
Electrolytes (serum)
Sodium	Decreases to 130-135 mmol/L
Bicarbonate	Decreases to 18-22 mmol/L
Potassium	Unchanged
Calcium (ionized)	Unchanged
Magnesium	Unchanged
Chloride	Unchanged
Phosphorus	Unchanged
Renal blood flow	Increases by ≈80% compared to prepregnancy levels
Renal protein excretion	Increases
pH	Increases
Renal aldosterone action	Increases
Renin-angiotensin action	Increases
Serum uric acid	Decreases to 130-135 mmol/L
Glomerular filtration rate	Increases by ≈50% compared to prepregnancy levels