Renal volume increase during pregnancy is approximately what percent?

• A. 10%
• B. 20%
• C. 30%
• D. 40%

Answer: (C)

During pregnancy the kidneys adapt to a higher workload by increasing both blood flow and filtration, which causes them to enlarge modestly. The commonly cited value for renal volume increase is about 30%, so the kidneys become roughly 1.3 times their nonpregnant size. This reflects the hyperfiltration state and greater renal perfusion that occur to support the mother and fetus. A smaller increase (around 10–20%) would underrepresent the physiologic changes, while a much larger jump (40%) would exceed what is typically observed.