This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Gynaecology & Obstetrics
In pregnancy following change takes place - 
Select and explain. 
A. Tidal volume increase, B. Arterial p02 decrease, C. Cardiac output decrease, D. Respiratory acidosis
A: Tidal volume increase
Answer: A: Tidal volume increase 
Explanation: Ans. is 'a' i.e., Tidal volume increase Respiratory changes during pregnancyo TLC is reduced by 5%o Subcostal angle increases from 69 to 103.o Tidal volume increases.o PaCO2 fall from 38 to 32 mnvhg & PaO2 rises from 95 t0 105 mm/hgo Pregnancy is a state of respiratory alkalosis.o Cardiac output increases during pregnancy, (already explained)