The change that does NOT occur during prgnancy is:

Correct option is B

Ans. (b)
Sol. During pregnancy, there is a decrease in the tone of the lower oesophageal sphincter due to hormonal changes, particularly increased levels of progesterone. This relaxation contributes to gastroesophageal reflux or heartburn, which is common in pregnant women.
Explanation of each option:
· (a) Increase in plasma volume – Correct physiological change. During pregnancy, plasma volume increases by about 40-50% to support the growing fetus and increased metabolic demands.
· (b) Increase in tone in the lower oesophageal sphincter – Incorrect. The tone actually decreases, leading to acid reflux and heartburn.
· (c) Low haematocrit – Correct physiological change. Due to a greater increase in plasma volume compared to red blood cell mass, haematocrit levels drop (physiological anemia of pregnancy).
· (d) Haemodilution – Correct physiological change. Increased plasma volume dilutes the concentration of red blood cells, leading to haemodilution.
Thus, the correct answer is (b) Increase in tone in the lower oesophageal sphincter since this change does NOT occur during pregnancy.