Bone mineral density measurement in puerperal women as a predictor of persistent osteopenia

The clinical value of bone mineral density (BMD) measurement in puerperal women is uncertain. Our aim was to examine the effectiveness of BMD measurement in puerperal women for identification of persistent osteopenia and osteoporosis. We addressed cross-sectional and longitudinal changes in BMD, assessed using dual-energy X-ray absorptiometry (DXA), in a postpartum female cohort from a single center in Japan. We measured BMD of the lumbar spine (L2–L4) with DXA in 2,436 puerperal women within 7 days of delivery (study 1). For 210 of the women, the BMD was measured again after 5–10 years (study 2). In study 1, 8 (0.3%) of the women were osteoporotic, 37 (17.0%) were osteopenic, and 2,013 (82.6%) were normal. In study 2, 27 (71.1%) of the 38 osteoporotic or osteopenic women identified in the puerperal scan were still osteopenic at the scan after 5–10 years. Over the same period, only 7 (4.1%) of 172 initially normal women became osteopenic. The mean of the BMD change per year was 0.15 ± 0.82%/year. Osteopenia was associated with a significantly lower body weight and body mass index at puerperium and after 5–10 years compared to normal women. The multiple regression analysis showed that BMD at the first scan negatively contributed and body weight changes between the scans positively significantly contributed to the BMD changes per year. Puerperal BMD remained static over the subsequent 5–10 years. If the women have a low BMD at this stage of their reproductive life, it tends not to improve over this time. Perhaps identification of this at-risk group may lead to effective interventions to reduce fracture risk in later life.