Pregnancy and lactation have no long-term deleterious effect on measures of bone mineral in healthy women: a twin study.

Background: The long-term effects of pregnancy and lactation on measures of bone mineral in women remain unclear.

Objective: We studied whether pregnancy or lactation has deleterious long-term effects on bone mineral in healthy women.

Design: We measured bone mineral density (BMD; g/cm(2)) in women aged > or = 18 y.

Hormone replacement therapy and bone mineral density: a co-twin approach.

Objective: Our objective was to estimate the difference in bone mass at clinically relevant sites within female twin pairs who were discordant for use of hormone replacement therapy (HRT).

Methods: We studied 46 female twin pairs who were discordant for HRT use. Bone mineral content and density were measured at the lumbar spine, total hip, femoral neck, 13 total forearm, and the total body.