Serum Creatinine Levels Before, During, and After Pregnancy

Abstract

Estimating renal function before and during pregnancy has clinical importance: kidney dysfunction can affect maternal and perinatal health. Glomerular hyperfiltration is a typical physiological adaptation to pregnancy, reflected by a decrease in levels of serum creatinine (SCr) with advancing gestational age. Creatinine-based equations used to estimate glomerular filtration may misclassify renal function during pregnancy, 1 as they depend on a steady state of creatinine balance. Moreover, a 24-hour collection of urine to measure cre-atinine clearance is impractical. 2 Accordingly, physicians typically rely on SCr level. Previous studies attempted to define a normal SCr level in pregnancy, but they had few participants and may have been confounded by sampling bias. 3,4 The current study was undertaken to generate gestational age-specific estimates of renal function-before, during, and after pregnancy-among women without antecedent kidney disease.

Clinical practice guideline on pregnancy and renal disease

“…Analysis of cross sectional serum creatinine concentrations from 243,534 pregnant women in Ontario, Canada defined mean serum creatinine as 60 μmol pre-pregnancy, falling to a nadir of 47 μmol between 16 and 32 weeks’ gestation, peaking at 64 μmol within the first post-partum weeks, before returning to pre-pregnancy concentrations by 18 weeks post-partum. The 95th centile values for serum creatinine were 78 μmol prior to pregnancy, 59 μmol during the second trimester, and 84 μmol in the post-partum period [121]. Meta-analysis of serum creatinine values in pregnancy suggests that the upper reference limits for serum creatinine in pregnancy are 85, 80 and 86% of non-pregnant reference values in the first, second and third trimesters respectively [122].…”

Safety and efficacy of Option B+ ART in Malawi: few severe maternal toxicity events or infant HIV infections among pregnant women initiating tenofovir/lamivudine/efavirenz

“…Checking glomerular filtration rate (eGFR) or creatinine clearance (CrCl) is recommended instead of serum creatinine to monitor renal function because serum creatinine changes are the least sensitive marker of renal function decline . However, serum creatinine may still be a useful measure of renal function during pregnancy . Our study was only able to use serum creatinine to monitor renal function, thus the data may have underestimated true reduced renal function among participants.…”

“…Checking glomerular filtration rate (eGFR) or creatinine clearance (CrCl) is recommended instead of serum creatinine to monitor renal function because serum creatinine changes are the least sensitive marker of renal function decline [32]. However, serum creatinine may still be a useful measure of renal function during pregnancy [33].…”

The Changing Landscape of Acute Kidney Injury in Pregnancy from an Obstetrics Perspective

“…Though there have been several studies that aimed at defining the reference values for serum creatinine, none are considered accurate in pregnancy [23,25,26]. A recent systematic review found that, using a nonpregnant reference interval of 45–90 mmol/L (0.51–1.02 mg/dL), a serum creatinine higher than 77 mmol/L (0.87 mg/dL) should be considered pathological, outside the normal range for pregnancy [23] (Table 1).…”

“…A recent systematic review and meta-analysis found that serum creatinine levels higher than 77 μmol/L (0.87 mg/dL) should be considered outside the normal range for pregnancy [23]. A more recent Canadian study, aiming to define gestational age-specific estimates of renal function, reported the ranges of serum creatinine in normal term pregnancy between 53–70 μmol/L, with an average of 61 μmol/L [26]. Therefore, acute increase in levels of creatinine during pregnancy above these levels, in an otherwise healthy woman, should prompt investigations into the cause of such occurrence.…”