Bone mineral changes during pregnancy: a cross-sectional study
Keywords:Bone mineral density, DEXA, Forearm, Pregnancy, Radius
Background: Changes in bone mineral density during pregnancy are not widely studied because of the risk of radiation hazard to the fetus. But newer technology like DEXA has made it possible to measure bone density accurately with low dose radiations which are safe even during pregnancy. The aim of this study was to evaluate the changes in maternal bone turnover markers and bone mineral content at forearm during pregnancy.
Methods: A total of 32 pregnant women with singleton pregnancy of more than thirty five weeks gestational age and thirty non-pregnant, non-lactating women as controls were recruited. Baseline blood investigations, serum calcium, serum alkaline phosphatase and DEXA of the forearm at ultra-distal, mid radius and proximal 1/3rd of radius were done at the time of recruitment into the study.
Results: Bone mineral density of forearm of pregnancy group was compared with non-pregnant, non-lactating control group to see the effect of pregnancy. Bone turnover markers like serum calcium and serum ALP were also compared among pregnancy group and controls. The mean bone mineral density of controls at ultra-distal radius was 0.437±0.058g/cm2, while in pregnant women it was 0.431±0.58g/cm2 that was not statistically significant. Bone mineral density at mid radius in control was 0.599±0.051g/cm2 and in pregnant women it was 0.597±0.048 g/cm2 with no significant difference. BMD at proximal 1/3rd radius in controls was 0.670±0.36 g/cm2 as compared to pregnant women where it was 0.660±0.036 g/cm2 without any statistical significance. Total BMD at forearm in control and pregnant women was 0.586±0.035 and 0.582±0.036 respectively and again there was no statistically significant difference.
Conclusions: There is no significant impact of pregnancy on bone mineral density of forearm. Although more bone areas need to be investigated for the further confirmation.
Widdowson EM. in: Scientific foundation of paediatrics.Davis JA and Dobbings J(eds)Wm Heinemann Medical Books: London; 1998.
Kovacs SC. Calcium and bone metabolism during pregnancy and lactation. J Mamm Gland Bio Neo 2005;10(2):105-18.
Kovacs CS, Kroneberg HM. Maternal-fetal calcium and bone metabolism during pregnancy, puerperium and lactation. Endocr Rev. 1997;18(6):832-72.
Christiansen C, Roedbro R, Heinild B. Unchanged total body calcium in normal human pregnancy. Acta Obstet Gynecol Scand. 1976;55:141-3.
Sowers MF, Scholl T, Harris L, Jannausch M. Bone loss in adolescent and adult pregnant women. Obstet Gynecol. 2000;96:189-93.
Priti K, Chandravati, Khattar R. Bone morbidity in pregnant women. J Obstet Gynecol India. 2005;55(5):434-5.
Kent GN, Price RI, Gutteridge DH, Smith M. Allen JR, Barnes MP. Human lactation-forearm trabecular bone loss, increased bone turnover and renal conservation of calcium and inorganic phosphate with recovery of bone mass following weaning. J Bone Miner Res. 1990;5(4):361-9.
Cross NA, Hillman LS, Allen SH, Krause GF. Calcium homeostasis and bone metabolism during pregnancy, lactation and weaning; a longitudinal study. Am J Clin Nutr. 1995;61:514-23.
Ritchie LD, Fung EB, Halloran BP. A longitudinal study of calcium homeostasis during human pregnancy and lactation and after resumption of menses. Am J Clin Nutr. 1998;67(4):693-701.
Heaney RP, Skillman TG. Calcium metabolism in normal human pregnancy. J Clin Endocrinol. 1971;33:661-70.
Sowers M, Randolph J, Shapiro B, Jannausch M. A prospective study of bone density and pregnancy after an extended period of lactation and bone loss. Obstet Gynecol. 1995;85:285-9.
Lamke B, Bruindin J. Moberg P. Charges of bone mineral content during pregnancy and lactation. Acta Obstet Gynecol Scand. 1977;56 (3);217-9.
Drinkwater BL, Chesnut CH. 3rd- bone density changes during pregnancy and lactation in active women; a longitudinal study. Bone Miner. 1991;14(2):153-60.
Kolthoff N, Eiken P, Kristensen B, Nielsen SP. Bone mineral changes during pregnancy and lactation: a longitudinal cohort study. Clin Sci. 1998;94:405-12.
Ulrich U, Miller PB, Eyre DR, Chesnut CH, Schlebusch H. Bone remodeling and bone mineral density during pregnancy. Arch Gynecol Obstet. 2003;268:309-16.
Naylor KE, Iqbal P, Fledelius C, Fraser RB, Eastell R. The effect of pregnancy on bone density and bone turnover. J Bone Miner Ras. 2000;15(1):129-37.
More C, Bettembuk P, Bhattoa HP, Balogh A. The effects of pregnancy and lactation on bone mineral density. Osteoporos Int. 2001;12:732-7.
Hosking DJ. Calcium homeostasis in pregnancy. Clin Endocrinol. 1996;45:1-6.
Zeni SN, Ortela Soler CR, Lazzari A, Lope ZL. Interrelationship between bone turnover markers and dietary calcium intake in pregnant women: a longitudinal study. Bone. 2003;33(4):606-13.
Valenzuela GJ, Munson LA, Tarbaux NM, Farley JR. Time-dependent changes in bone, placental, intestinal and hepatic alkaline phosphatase activities in serum during human pregnancy. Clin Chem. 1987;33(10):1801-6.
Black AJ, Topping J, Durham B, Farquharson RG, Fraser WD. A detailed assessment of alterations in bone turnover, calcium homeostasis in normal pregnancy. J Bone Miner Res. 2000;15(3):557-63.