title: Pregnancy reduces the accuracy of the estimated glomerular filtration rate based on Cockroft-Gault and MDRD formulas.
abstract: OBJECTIVE
  This study aims to determine the effect of pregnancy on the accuracy of 3 commonly used methods to estimate glomerular filtration rate ([GFR] creatinine clearance, the Cockroft-Gault, and modification of diet in renal disease [MDRD] formulas) using the inulin clearance as a reference.
  
  
  METHODS
  Longitudinal study design.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  A total of 44 parous nonsmoking Caucasian women. They had a history of uneventful pregnancy (n = 9), preeclampsia (n = 27), and intrauterine fetal demise (n = 8).
  
  
  METHODS
  Measurements were performed both in pre-pregnancy and early pregnancy (8 weeks of gestation) and included inulin infusion, blood pressure, and 24-hour urinary and serum creatinine. Agreement between methods to estimate GFR was assessed by the Bland and Altman method.
  
  
  METHODS
  GFR estimated by inulin and creatinine clearances and the Cockroft-Gault and MDRD formulas.
  
  
  RESULTS
  During early pregnancy, the GFR measured by inulin increased 32% compared with the pre-pregnant value (from 115 ± 18 to 150 ± 23 mL/min·1.73 m(-2)), whilst the GFR measured by the indirect methods only increased 20%. The observed bias and limits of agreements are larger in early pregnancy relative to the pre-pregnant state for all 3 methods.
  
  
  CONCLUSIONS
  The renal hyperfiltration during pregnancy decreases further the accuracy of the creatinine clearance and the Cockroft-Gault and MDRD formulas to estimate GFR.
authors.affiliation: Department of Obstetrics and Gynecology, Maastricht University Medical Centre, Maastricht, Netherlands.
authors.forename: Patricia M J L
authors.initials: PM
authors.lastname: Koetje
authors.forename: Julia J
authors.initials: JJ
authors.lastname: Spaan
authors.forename: Jeroen P
authors.initials: JP
authors.lastname: Kooman
authors.forename: Marc E A
authors.initials: ME
authors.lastname: Spaanderman
authors.forename: Louis L
authors.initials: LL
authors.lastname: Peeters
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D003404:Creatinine / Q000378:metabolism; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007444:Inulin / Q000378:metabolism; D007674:Kidney Diseases / Q000175:diagnosis / Q000378:metabolism; D007677:Kidney Function Tests / Q000379:methods / Q000592:standards*; D008137:Longitudinal Studies; D008657:Metabolic Clearance Rate / Q000502:physiology; D011247:Pregnancy / Q000378:metabolism*; D011248:Pregnancy Complications / Q000175:diagnosis / Q000378:metabolism; D013223:Statistics as Topic
chemical_list: D007444:Inulin; D003404:Creatinine