At birth, the neonatal skeleton contains 20 to 30 g calcium (Ca). It is hypothesized maternal bone mineral may be mobilized to support fetal skeletal development, although evidence of pregnancy‐induced mineral mobilization is limited. We recruited healthy pregnant (n = 53) and non‐pregnant non‐lactating (NPNL; n = 37) women aged 30 to 45 years (mean age 35.4 ± 3.8 years) and obtained peripheral quantitative computed tomography (pQCT) and high‐resolution pQCT (HR‐pQCT) scans from the tibia and radius at 14 to 16 and 34 to 36 weeks of pregnancy, with a similar scan interval for NPNL. Multiple linear regression models were used to assess group differences in change between baseline and follow‐up; differences are expressed as standard deviation scores (SDS) ± SEM. Decreases in volumetric bone mineral density (vBMD) outcomes were found in both groups; however, pregnancy‐related decreases for pQCT total and trabecular vBMD were −0.65 ± 0.22 SDS and −0.50 ± 0.23 SDS greater (p  < .05). HR‐pQCT total and cortical vBMD decreased compared with NPNL by −0.49 ± 0.24 SDS and −0.67 ± 0.23 SDS, respectively; trabecular vBMD decreased in both groups to a similar magnitude. Pregnancy‐related changes in bone microarchitecture significantly exceeded NPNL change for trabecular number (0.47 ± 0.23 SDS), trabecular separation (−0.54 ± 0.24 SDS), cortical thickness (−1.01 ± 0.21 SDS), and cortical perimeter (0.78 ± 0.23 SDS). At the proximal radius, cortical vBMD and endosteal circumference increased by 0.50 ± 0.23 SDS and 0.46 ± 0.23 SDS, respectively, compared with NPNL, whereas cortical thickness decreased −0.50 ± 0.22 SDS. Pregnancy‐related decreases in total and compartment‐specific vBMD exceed age‐related change at the distal tibia. Changes at the radius were only evident with pQCT at the cortical‐rich proximal site and suggest endosteal resorption. Although the magnitude of these pregnancy‐related changes in the appendicular skeleton are small, if they reflect global changes across the skeleton at large, they may contribute substantially to the Ca requirements of the fetus. © 2020 Crown copyright. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

中文翻译：

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30 至 45 岁女性与妊娠相关的骨矿物质和微结构变化。

出生时，新生儿骨骼含有 20 至 30 克钙 (Ca)。假设母体骨矿物质可能被调动以支持胎儿骨骼发育，尽管妊娠诱导的矿物质动员的证据有限。我们招募了健康孕妇 ( n = 53) 和非妊娠非哺乳期 (NPNL; n= 37) 30 至 45 岁的女性（平均年龄 35.4 ± 3.8 岁），并在 14 至 16 岁和 34 至 36 岁时获得了胫骨和桡骨外周定量计算机断层扫描 (pQCT) 和高分辨率 pQCT (HR-pQCT) 扫描怀孕几周，NPNL 的扫描间隔相似。多元线性回归模型用于评估基线和随访之间变化的组差异；差异表示为标准偏差分数 (SDS) ± SEM。两组均发现体积骨矿物质密度（vBMD）结果降低；然而，pQCT 总和小梁 vBMD 与妊娠相关的降低分别为 -0.65 ± 0.22 SDS 和 -0.50 ± 0.23 SDS（p < .05)。与 NPNL 相比，HR-pQCT 总和皮质 vBMD 分别降低了 -0.49 ± 0.24 SDS 和 -0.67 ± 0.23 SDS；两组的骨小梁 vBMD 下降幅度相似。妊娠相关的骨微结构变化显着超过小梁数量（0.47 ± 0.23 SDS）、小梁分离（-0.54 ± 0.24 SDS）、皮质厚度（-1.01 ± 0.21 SDS）和皮质周长（0.78 ± 0.23 SDS）的 NPNL 变化. 在桡骨近端，与 NPNL 相比，皮质 vBMD 和骨内膜周长分别增加了 0.50 ± 0.23 SDS 和 0.46 ± 0.23 SDS，而皮质厚度减少了 -0.50 ± 0.22 SDS。与妊娠相关的总和特定隔室 vBMD 的下降超过了胫骨远端与年龄相关的变化。桡骨的变化仅在富含皮质的近端部位的 pQCT 中明显，提示骨内膜吸收。尽管这些与妊娠相关的附肢骨骼变化的幅度很小，但如果它们反映了整个骨骼的整体变化，它们可能对胎儿的钙需求有很大贡献。© 2020 皇冠版权。由 Wiley Periodicals LLC 代表美国骨骼和矿物研究协会 (ASBMR) 出版的《骨骼和矿物研究杂志》。本文经 HMSO 总监和苏格兰女王印刷局许可发布。