title: Letter: Calcium balance in pregnancy.
mesh_terms: D044383:Black People; D002118:Calcium / Q000378:metabolism*; D002136:Calcium, Dietary / Q000008:administration & dosage*; D005260:Female; D005333:Fetus / Q000378:metabolism; D006801:Humans; D007774:Lactation; D009751:Nutritional Requirements; D011247:Pregnancy; D013019:South Africa; D044465:White People
chemical_list: D002136:Calcium, Dietary; D002118:Calcium