Creatinine clearance (CrCl) increases during normal pregnancy because of higher renal blood flow and increased glomerular filtration rate (GFR). These values represent typical trimester-specific reference ranges.
| Units | Non-pregnant Adult | 1st Trimester | 2nd Trimester | 3rd Trimester |
|---|---|---|---|---|
| mL/min | 91–130 | 69–140 | 55–136 | 50–166 |
Causes of High Creatinine Clearance (Increased GFR)
- Normal physiologic hyperfiltration in pregnancy
- High protein intake
- Early diabetic hyperfiltration
- Obesity
- Early glomerulonephritis with hyperfiltration
- SGLT-2 inhibitors (initial rise in GFR)
- Incomplete urine collection → falsely elevated CrCl
Causes of Low Creatinine Clearance (Reduced GFR)
- Chronic kidney disease
- Acute kidney injury
- Preeclampsia (glomerular endotheliosis)
- Dehydration / hypovolemia
- Obstructive uropathy
- Heart failure (reduced renal perfusion)
- Medications:
- NSAIDs
- Calcineurin inhibitors (tacrolimus, cyclosporine)
- IV contrast
- Under-collection of urine → falsely low CrCl
- Low muscle mass (reduced creatinine production)
References
- Abbassi-Ghanavati M, Greer LG, Cunningham FG. Pregnancy and laboratory studies: a reference table for clinicians. Obstet Gynecol. 2009;114:1326–1331. PMID: 19935037