Lumbar bone mineral density changes during pregnancy and lactation

• Published in: International journal of gynecology and obstetrics 1998-12, Vol.63 (3), p.253-258
• Main Authors: Honda, A., Kurabayashi, T., Yahata, T., Tomita, M., Takakuwa, K., Tanaka, K.
• Format: Article
• Language: English
• Subjects: Absorptiometry, Photon; Adult; Alkaline Phosphatase - blood; Biological and medical sciences; Bone Density - physiology; Cross-Sectional Studies; Dual energy X-ray absorptiometry; Estradiol; Estradiol - blood; Female; Fundamental and applied biological sciences. Psychology; Humans; Lactation; Lactation - metabolism; Lumbar Vertebrae - diagnostic imaging; Lumbar Vertebrae - metabolism; Pregnancy; Pregnancy - metabolism; Prolactin; Prolactin - blood; Skeleton and joints; Vertebrates: osteoarticular system, musculoskeletal system
• ISSN: 0020-7292; 1879-3479
• DOI: 10.1016/S0020-7292(98)00155-6

Objective: To elucidate the change of bone metabolism in the lumbar trabecular and its relationship with serum hormonal changes in pregnancy and lactation. Study design: In a cross-sectional study, we measured the bone mineral density (BMD) of 2–4 lumbar vertebrae of 571 puerperae at days 3–5 postpartum and 341 healthy, non-pregnant women (control subjects) of approximately the same age by dual energy X-ray absorptiometry. In a longitudinal study, we also measured the BMD of 111 puerperae at 3 and 6 months after delivery. Results: The mean BMD at days 3–5 postpartum was significantly lower than that of the control (1.013 ± 0.005 vs. 1.032 ± 0.006 g/cm 2, P = 0.019). The lactating group showed BMD decrement to 95.1 ± 0.5% ( n = 69) and 94.1 ± 0.7% ( n = 61) at 3 and 6 months postpartum, respectively, compared with days 3–5 postpartum, and the amenorrhea group showed the same tendency. The non-lactating group and resumption of menses group did not show a BMD decrement postpartum. In the lactating group, serum estradiol was significantly lower than in the non-lactating group at 3 months postpartum, serum prolactin and bone alkaline phosphatase levels were higher than in the non-lactating group at 3 and 6 months postpartum. Conclusions: Pregnancy may cause a decrease of lumbar BMD, and the lactation and amenorrhea also cause a decrease of BMD. In addition to lactation status, the ovarian dysfunction is one of the factors in bone loss during lactation.