This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Physiological changes during Pregnancy, Subject name: Gynaecology & Obstetrics
[{'content': 'False regarding calcium homeostasis in pregnancy is? \nSelect and explain. \nA. Serum non ionized calcium levels fall, B. Serum ionized calcium levels fall, C. Intestinal absorption of calcium increased, D. Levels of 1,25 dihydroxy vitamin D are increased', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. Serum ionized calcium levels fallTotal serum calcium levels, (which include both ionized and non-ionized calcium), decline during pregnancy, reduction follows lowered plasma albumin concentrations and, a consequent decrease in the amount of circulating protein- bound non ionized calcium. Serum ionized calcium levels remain unchanged. The fetal skeleton accretes approximately 30g of calcium by term, 80 percent of which is deposited during the third trimester. This demand is largely met by a doubling of maternal intestinal calcium absorption mediated, in part, by 1,25-dihydroxyvitamin D3 . Dietary intake of sufficient calcium is necessary to prevent excess depletion from the mother.', 'role': 'assistant'}]