Bone mineral content in relation to lactation history in pre- and postmenopausal women.

Bone mineral content in the lumbar spine was studied in relation to lactation history and number of live births in 126 pre- and postmenopausal Swedish women. Total number of months of breastfeeding was significantly associated with low bone mineral content, and the strength of the association was greatly enhanced by statistical adjustment for menopausal status and body weight. Women with higher parity also had lower bone mineral content, but this observation could be attributed to more breastfeeding among that group.