title: Urinary excretion rates of calcium and magnesium in normal and complicated pregnancies.
abstract: In this cross-sectional study calcium and magnesium metabolism was investigated in normal pregnancies (n = 34) and pregnancies complicated by either fetal growth retardation of hypertension with or without fetal growth retardation (SGA newborns) (n = 30). Special attention has been given to the renal excretion rates of calcium and magnesium and their relationship to creatinine and sodium clearances. No differences were noted in the third trimester of pregnancy between the normal and complicated pregnancies in calcium or magnesium metabolism except for an increased serum magnesium in the SGA group. Comparing the post-partum period to normal pregnancy the following results were observed: (i) serum ionic calcium levels showed no differences; (ii) urinary calcium excretion was increased as a result of increased calcium clearance. A striking feature was the fact that the fractional calcium clearance was not increased, in contrast to the increase in relative calcium clearance. The observed results can be explained by an increased GFR and a possible dissociation between the sodium and calcium handling in the cortical thick ascending Limb of Henle's Loop.
authors.affiliation: Department of Obstetrics and Gynaecology, Streekziekenhuis Helmond-Deurne, Helmond, The Netherlands.
authors.forename: J M
authors.initials: JM
authors.lastname: Roelofsen
authors.forename: G M
authors.initials: GM
authors.lastname: Berkel
authors.forename: O T
authors.initials: OT
authors.lastname: Uttendorfsky
authors.forename: J F
authors.initials: JF
authors.lastname: Slegers
mesh_terms: D001724:Birth Weight; D002118:Calcium / Q000652:urine*; D005260:Female; D005317:Fetal Growth Retardation / Q000150:complications; D006706:Homeostasis; D006801:Humans; D006973:Hypertension / Q000652:urine*; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008274:Magnesium / Q000652:urine*; D011247:Pregnancy / Q000652:urine*; D011249:Pregnancy Complications, Cardiovascular / Q000652:urine*
chemical_list: D008274:Magnesium; D002118:Calcium