Pregnancy is a physiological condition during which metabolic and structural changes occur in the skeleton aimed at supplying the fetus with the required calcium. As a consequence, several physiological mechanisms of adaptation usually develop in response to these changes for maintaining the mechanical properties of the skeleton.
However, studies on the assessment of changes in the bone structure during pregnancy have focused mostly on data before pregnancy and in the post-partum period.
Breasail et al. have recently reported data on the microstructural characteristics of bone assessed at the tibia and radius during pregnancy. The authors have employed the peripheral quantitative computed tomography (pQCT) and, for the first time, the high resolution pQCT (HR-pQCT) to the study of the trabecular and cortical microstructure in pregnant women aged 30-45. They found specific changes associated with pregnancy, according to the compartment and the site studied. In particular, they observed decreased cortical volumetric BMD and thickness, increased trabecular number and decreased trabecular separation at tibia, but not at radius. Authors suggest that bone is presumably mostly degraded at the trabecular level in response to fetus requirement of calcium during pregnancy, while structural adaptations occur at the cortical level. This would be evident exclusively at the load-bearing skeletal sites.
HR-pQCT is the gold standard in the non-invasive assessment of bone microstructure and the new data open interesting question on the physiological mechanisms involved in the metabolic bone changes during pregnancy. How these metabolic perturbations could impact the structural and mechanical properties of the skeleton in pregnant women and possible outcomes in the future life need further evaluation.