title: A systematic review and meta-analysis of hypocalciuria in pre-eclampsia.
abstract: BACKGROUND
  Small observational studies have demonstrated that pre-eclampsia is associated with hypocalciuria.
  
  
  OBJECTIVE
  To compare urinary calcium excretion in pre-eclampsia, gestational hypertension, and chronic hypertension with that in normotensive pregnancies.
  
  
  METHODS
  Online databases were searched through February 2016 using medical subject headings "calcium homeostasis," "calcium excretion," "hypocalciuria," and "pre-eclampsia."
  
  
  METHODS
  Observational studies were included that evaluated calcium excretion with 24-hour urine collection in patients with pre-eclampsia compared with normotensive pregnant women.
  
  
  METHODS
  Data were extracted from identified studies. The primary outcome was 24-hour urinary calcium excretion. Weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated.
  
  
  RESULTS
  Twenty-one studies were included. Urinary calcium excretion was lower among women with pre-eclampsia than among those with normotensive pregnancies (WMD -158.43, 95% CI -187.95 to -128.92) or chronic hypertension (WMD -92.92, 95% CI -100.55 to -85.29). Excretion was also reduced in severe versus mild pre-eclampsia (WMD -35.00, 95% CI -58.94 to -11.07) and gestational hypertension versus normotensive pregnancies (WMD -50.95, 95% CI -57.74 to -44.17). Calcium excretion was not significantly lower in chronic hypertension versus normotensive pregnancies (WMD -64.45, 95% CI -135.98 to 7.08).
  
  
  CONCLUSIONS
  Urinary calcium excretion decreases with increasing severity of pregnancy-induced hypertensive disorders, but this trend is not observed in chronic hypertension.
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: Kristen M
authors.initials: KM
authors.lastname: McMaster
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Florida College of Medicine - Jacksonville, Jacksonville, FL, USA.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Kaunitz
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Florida College of Medicine - Jacksonville, Jacksonville, FL, USA.
authors.forename: Prardhana
authors.initials: P
authors.lastname: Burbano de Lara
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Florida College of Medicine - Jacksonville, Jacksonville, FL, USA.
authors.forename: Luis
authors.initials: L
authors.lastname: Sanchez-Ramos
mesh_terms: D002118:Calcium / Q000378:metabolism / Q000652:urine*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D006973:Hypertension / Q000378:metabolism / Q000652:urine; D046110:Hypertension, Pregnancy-Induced / Q000378:metabolism / Q000652:urine; D011225:Pre-Eclampsia / Q000378:metabolism / Q000652:urine*; D011247:Pregnancy / Q000652:urine
chemical_list: D002118:Calcium
keywords: Calcium excretion; Gestational hypertension; Hypertension; Hypocalciuria; Pre-eclampsia; Urinary calcium