In the setting of 24-hydroxylase deficiency, this increase in 1,25(OH)2D may be exaggerated during pregnancy, leading to hypercalcemia.8 Furthermore, women may remain asymptomatic and normocalcemic until exposed to prenatal vitamins and physiologic changes of pregnancy, including increased uteroplacental PTHrP and vitamin D activation.4,9,10. This evidence concerns the gene PTHLH and hypercalcemia disease.