Breasail MO, et al. - The neonatal skeleton is identified containing 20 to 30 g calcium (Ca) at birth. Possibly maternal bone mineral mobilization occurs to support the fetal skeletal development, however, there is limited evidence of pregnancy‐induced mineral mobilization. Researchers here sought to determine the extent of pregnancy‐induced changes in compartmental (trabecular and cortical) volumetric bone mineral density (vBMD) and bone mineral microarchitecture using peripheral quantitative computed tomography (pQCT) and high resolution (HR)‐pQCT techniques between the early second (14 to 16 weeks) and the third trimester (34 to 36 weeks) in UK women aged 30 to 45 years. Among 53 recruited healthy pregnant and 37 non‐pregnant non‐lactating (NPNL; n = 37) women, pQCT and HR‐pQCT scans were obtained from the tibia and radius at 14 to 16 and 34 to 36 weeks of pregnancy in pregnant women, with a similar scan interval for NPNL. Both groups had decreases in vBMD outcomes; however, pregnancy‐related decreases for pQCT total and trabecular vBMD were greater. Decreased HR‐pQCT total and cortical vBMD were noted compared with NPNL; both groups showed decrease in trabecular vBMD of similar magnitude. They identified significantly high pregnancy‐related changes in bone microarchitecture relative to NPNL change for trabecular number, trabecular separation, cortical thickness, and cortical perimeter. At the proximal radius, there was an increase in cortical vBMD and endosteal circumference compared with NPNL, whereas there was a decrease in cortical thickness. Relative to age‐related change at the distal tibia, there were higher pregnancy‐related decreases in total and compartment‐specific vBMD. Only pQCT showed changes at the radius at the cortical‐rich proximal site and indicated endosteal resorption. Although these pregnancy‐related changes in the appendicular skeleton are small in magnitude, they may contribute substantially to the Ca requirements of the fetus if they indicate global changes across the skeleton at large.