Objective: To explore the effects of pregnancy and postpartal lactation on bone mineral density (BMD).
Methods: In this study, the BMD of 22 pregnant women in a longitudinal study, and of 75 pregnant and 111 puerperant women in a cross-sectional study was estimated at the distal radius of the forearm by dual energy X-ray absorptiometry. BMD was measured on 8 separate occasions from the first trimester of pregnancy to 24 months' postpartum.
Results: In none of 22 pregnant women was there any noticeable change in BMD during pregnancy. Whereas no significant change in BMD occurred during the 12-month postpartum period in 11 non-lactating women, 11 women who breastfed had a significant decrease in BMD at 1, 3, and 6 months' postpartum, with all of them showing a further decrease in BMD at 12 months' postpartum. The BMD of the radius was significantly lower in the breast-feeders than in the formula-feeders at all postpartal times of evaluation except at 24 months' postpartum.
Conclusion: It can be recommended that lactating women receive appropriate treatments for saving BMD during lactation.