During pregnancy, the bicarbonate level (HCO3) is typically in which range?

• A. 16-22 mEq/L
• B. 24-26 mEq/L
• C. 28-30 mEq/L
• D. 34-36 mEq/L

Answer: (A)

During pregnancy, the body’s acid-base balance shifts toward a mild respiratory alkalosis because ventilation increases. The kidneys respond by excreting more bicarbonate to compensate, so the bicarbonate level falls. This makes the typical pregnancy baseline lower than the nonpregnant reference. So the best choice is the range that sits at the lower end of the normal bicarbonate values. Higher or normal-range bicarbonate levels would not reflect the usual pregnancy adaptation and would point away from the expected physiologic change.