OBJECTIVE: The purpose of this study was to examine the hormones regulating calcium homeostasis longitudinally in pregnancy and post partum. STUDY DESIGN: Twenty-three women with normal pregnancies were studied in the second and third trimesters and post partum. At each time blood was analyzed for ionized calcium, vitamin D metabolites, and intact parathyroid hormone, and a 24-hour urine specimen was analyzed for creatinine, calcium, and sodium. RESULTS: Urinary calcium excretion was 250% to 300% higher during pregnancy than post partum (p < 0.00001). 1,25-Dihydroxyvitamin D levels were equivalent in the second and third trimesters but were twofold higher than postpartum values (p < 0.01). Ionized calcium was similar at all time points. Intact parathyroid hormone in the second and third trimesters was 50% of postpartum levels (p < 0.001). CONCLUSION: Pregnancy is associated with an increase in the levels of 1,25-dihydroxyvitamin D and a concomitant reciprocal fall in intact parathyroid hormone levels. The increase in serum 1,25-dihydroxyvitamin D values appears to be a key factor in providing for the increase in maternal calcium requirements during pregnancy.
OBJECTIVE: The purpose of this study was to examine the hormones regulating calcium homeostasis longitudinally in pregnancy and post partum. STUDY DESIGN: Twenty-three women with normal pregnancies were studied in the second and third trimesters and post partum. At each time blood was analyzed for ionizedcalcium, vitamin D metabolites, and intact parathyroid hormone, and a 24-hour urine specimen was analyzed for creatinine, calcium, and sodium. RESULTS: Urinary calcium excretion was 250% to 300% higher during pregnancy than post partum (p < 0.00001). 1,25-Dihydroxyvitamin D levels were equivalent in the second and third trimesters but were twofold higher than postpartum values (p < 0.01). Ionizedcalcium was similar at all time points. Intact parathyroid hormone in the second and third trimesters was 50% of postpartum levels (p < 0.001). CONCLUSION: Pregnancy is associated with an increase in the levels of 1,25-dihydroxyvitamin D and a concomitant reciprocal fall in intact parathyroid hormone levels. The increase in serum 1,25-dihydroxyvitamin D values appears to be a key factor in providing for the increase in maternal calcium requirements during pregnancy.
Authors: Bridget E Young; Thomas J McNanley; Elizabeth M Cooper; Allison W McIntyre; Frank Witter; Z Leah Harris; Kimberly O O'Brien Journal: J Bone Miner Res Date: 2012-01 Impact factor: 6.741
Authors: Kimberly O O'Brien; Carmen M Donangelo; Lorrene D Ritchie; Ginny Gildengorin; Steve Abrams; Janet C King Journal: Am J Clin Nutr Date: 2012-05-30 Impact factor: 7.045
Authors: Augusto A Litonjua; Nancy E Lange; Vincent J Carey; Stacey Brown; Nancy Laranjo; Benjamin J Harshfield; George T O'Connor; Megan Sandel; Robert C Strunk; Leonard B Bacharier; Robert S Zeiger; Michael Schatz; Bruce W Hollis; Scott T Weiss Journal: Contemp Clin Trials Date: 2014-03-12 Impact factor: 2.226