CAMBRIDGE, England—Maternal bone mineral and mobilization is partly responsible for supplying calcium for fetal and neonatal bone growth and development. English researchers found calcium supplementation in pregnant women with low calcium intakes may disrupt metabolic adaptation and may not benefit maternal bone health (Am J Clin Nutr. 2010;92:450-57). In a subset of participants (n=125) in a double blind, randomized, placebo-controlled trial in pregnant women in The Gambia, West Africa, with low calcium intakes (350 mg/d), researchers measured bone mineral status of the whole body, lumbar spine and hip by using dual-energy X-ray absorptiometry, and measured bone mineral status of the forearm by using single-photon absorptiometry at two, 13 and 52 week lactation. Blood and urine was collected from the subjects at 20 week gestation and at 13 week postpartum. Participants received calcium carbonate (1,500 mg/d) or a matching placebo from 20 week gestation to parturition; participants did not consume supplements during lactation.
Women who received the calcium supplement in pregnancy had significantly lower bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) at the hip throughout 12 months of lactation. The women also experienced greater decreases in bone mineral during lactation at the lumbar spine and distal radius, and had biochemical changes consistent with greater bone mineral mobilization.
