Final answer:
Maternal bicarbonate is not low but high during pregnancy to compensate for respiratory alkalosis.
Step-by-step explanation:
The statement given, 'Maternal bicarbonate is low during pregnancy to compensate for respiratory alkalosis,' is false.
During pregnancy, there is an increase in respiratory hormones which lead to an increased respiratory rate. This hyperventilation results in a state called respiratory alkalosis, where there is an excessive loss of carbon dioxide (CO₂). To compensate for this alkalotic state, the kidneys excrete excess bicarbonate ions (HCO₃⁻) and retain hydrogen ions (H⁺) in order to bring the blood pH back to normal. To compensate for this, the kidneys excrete more bicarbonate, leading to lower levels of bicarbonate in maternal blood. This renal compensation helps to maintain the acid-base balance in the mother's body during pregnancy. Therefore, maternal bicarbonate is actually high during pregnancy to compensate for respiratory alkalosis.