A Comparison of Prediction Equations for Estimating Glomerular Filtration Rate in Pregnancy

Abstract

Objective: To compare existing glomerular filtration rate (GFR) prediction equations with the gold standard, inulin clearance, in pregnancy. Methods: Five equations were assessed for precision, bias, and accuracy in prediction of true GFR, measured by inulin clearance in 12 healthy, pregnant women during the second (T2) and third (T3) trimesters and in postpartum (PP). Results: Precision was greatest with 24-hour creatinine clearance estimation of GFR (R² = 13% (T2), R² = 26% (T3)). Other than 100/SCr, all equations underestimated true GFR. 30% accuracy was greatest in 100/SCr (83% (T2), 92% (T3)). Conclusions: Current GFR prediction formulae do not appear to be sufficient for estimating GFR in the gravid state.

Keywords:

• Pregnancy
• Glomerular filtration rate
• Prediction equation
• Inulin clearance
• Kidney