Proteinuria in Pregnancy

Introduction

During normal physiological conditions, the kidney functions as a crude molecular filter, passing small solutes freely along their concentration gradients, enabling water to be reabsorbed from the distal tubule, and preventing urinary loss of protein and large molecules. Maintenance of a steady glomerular filtration rate (GFR) is a vital aspect in homeostatic regulation. Kidney dysfunction is a common factor in a number of pregnancy complications including hypertensive conditions such as pre-eclampsia.¹

Abstract

Checking for proteinuria is routinely performed during every antenatal appointment both in primary and secondary as a screening test for pre-eclampsia. Even in the absence of raised blood pressure, the presence of significant proteinuria during the antenatal period is taken seriously, because proteinuria is perceived to be a diagnostic marker for maternal and fetal complications. The appearance of proteinuria prior to hypertension onset and the diagnosis of pre-eclampsia is well documented in the literature; hence, the presence of proteinuria per se warrants medical referral, investigations, and increased antenatal monitoring frequency. In this review, the authors examine the pathology relating to proteinuria, methods used in its biochemical assessment, and the current evidence relating to the diagnostic and prognostic accuracy of this test in relation to pre-eclampsia.

Keywords

proteinuria, toxaemia, pregnancy, kidney, hypertension