INS and Insulin resistance: The OC level increases to promote the release of insulin from pancreatic β cells as compensation for insulin resistance during pregnancy; however, no sufficient amounts of insulin are secreted because of a relative deficiency of pancreatic β cells, regardless of the increase in the OC level.15-17 It is suggested that the OC level rises as bone resorption markers increase, which promotes the occurrence GDM and induces bone mass loss, contributing to a lower BMD.18 BALP, PINP, and β-CTx are three vital BTMs mainly produced by and released from bones.