**Glomerular filtration rate (GFR) –**

MDRD formula- Creatinine-based formulae are inaccurate in pregnancy. The Modification of Diet in Renal Disease (MDRD) formula underestimates GFR by 40ml/min. Among pregnant women with preeclampsia or CKD, MDRD formula is slightly better, underestimating GFR by 23.3 and 27.3 ml/min respectively.

Creatinine clearance by24-h urine collection closely approximates GFR by inulin clearance among healthy pregnant women and is the gold standard in pregnancy.

Weight-based formulas such as Cockroft-Gault formulae overestimate GFR by approximately 40 ml/min.
