How Much Does Lactation Affect Bone Mineral Density?
Lactation causes significant hypoestrogenemia, which has negative effects on calcium and phosphate metabolism. Studies suggest that the decrease in bone mineral density averages 4 to 6 percent during the first six months of lactation. Polatti and colleagues evaluated variations in bone mineral density, with and without calcium supplementation, during lactation and during the 12 months after cessation of lactation. The lactation cohort included women who intended to breast feed for at least six months following vaginal term delivery. There were three groups in the study: 139 women who breast fed and received 1 g of calcium supplementation daily; 135 women who breast fed but did not receive calcium supplementation; and 153 women who did not breast feed and did not receive calcium supplementation. The three groups were comparable in all relevant variables. Bone mineral density of the radius and spine was measured within 10 days of delivery (baseline) and again at three, six, 12 and 18 mon
