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
Which of the following is the least likely physiological change in pregnancy : 
Select and explain. 
A. Increase in intravascular volume, B. Increase in cardiac output, C. Increase in stroke volume, D. Increase In peripheral vascular resistance
D: Increase In peripheral vascular resistance
Answer: D: Increase In peripheral vascular resistance 
Explanation: The increase in cardiac output does not cause increase in BP. This is due to massive fall in peripheral vascular resistance due to smooth muscle relaxant propeies of progesterone. Reference : Dutta's Textbook of Obstetrics 7th edition page 53