Jackie, This is from the abstract from LLL's 1997 Facts about Breastfeeding. The full paper can be found in Am J Clin Nutr 1996; 63(4):526-31. The title is Intestinal calcium absorption of women during lactation and after weaning. Authors: Kalkwarf, H.J. et al. I assume this study was done on healthy mothers, but maybe it will help. The fact sheet stated the following: Increased efficiency of calcium absorption from the intestine is one maternal physiologic adaptation used to meet the demand for calcium during lactation, but this response is only apparent after weaning or the resumption of menses. The increased fractional calcium absorption postweaning may be related to a gain in bone mineral density of the lumbar spine within 6 months of weaning. Hope this helps. Aloha, Gloria Thai LLLLeader Hawai'i