This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
Physiological changes in pregnancy : 
Select and explain. 
A. Decreased residual volume, B. Decreased GFR, C. Decreased Cardiac output, D. Increased Haematocrit
A: Decreased residual volume
Answer: A: Decreased residual volume 
Explanation: *The functional residual capacity and residual volume are decreased due to elevated diaphragm. GFR increases by 50% Cardiac output increases by 40% Hemoglobin and hematocrit decreases. Reference : William's Textbook of Obstetrics 24th edition page 62