在母亲怀孕期的最后三个月,胎儿每天从妈妈那里得到钙,即使妈妈有营养不良、胎盘功能不全或胎儿有营养不良,胎盘还是能够主动转送钙。因此,母体妊娠后自身的钙量减少,但胎儿血内的钙并不低,出生后,因母亲的供应突然停止,外源性的钙供给量很少,新生儿的血钙水平可在出生后几小时内持续下降24～ During the third trimester of pregnancy, fetuses receive calcium daily from their mothers and the placenta can actively deliver calcium even if the mother has malnutrition, placental insufficiency, or malnutrition in the fetus. Therefore, maternal pregnancy itself after the reduction of calcium, but fetal blood calcium is not low, after birth, due to a sudden stop of the mother’s supply, exogenous calcium supply is very small, neonatal calcium levels can be born After a few hours continued to decline 24 ~