Objectives: To determine if pregnancy after an extended period of lactation curtails the recovery of maternal bone mineral density.
Methods: Twenty-five women who fully breast-fed their infants for at least 6 months and had a subsequent pregnancy within 18 months of initiating lactation were studied longitudinally. Twenty controls breast-fed similarly, but had no subsequent pregnancy. The women were healthy, well-nourished, and between 20-40 years old. Bone mineral density was measured by dual x-ray energy absorptiometry at the spine and hip.
Results: Both cases and controls lost bone mineral density with extended lactation. The case group had a bone mineral density recovery comparable to the controls.
Conclusion: Women with the dual calcium demands of extended lactation and a subsequent pregnancy are not at risk for failure of bone recovery to pre-lactation levels.