Urinary Sodium to Creatinine and Calcium to Creatinine Ratios as a Marker in Diagnosis of Preeclampsia

Abstract

Preeclampsiais a leading cause of maternal and perinatal mortality and morbidity. Incidence of PE is 2 -8%, though exact cause of preeclampsia is unknown, the basic pathology is endothelial dysfunction and intense vasospasm.

With development of preeclampsia, there may be a number of reversible anatomical and pathophysiological changes. Of clinical importance, renal perfusion and glomerular filtration are reduced. Levels that are much less than normal non pregnant values are infrequent and are the consequence of severe disease.

A small degree of decreased glomerular filtration may result from reduced plasma volume. Most of the decrement, however, is from increased renal afferent arteriolar resistance that may be elevated up to five folds.

Several abnormalities of calcium metabolism such as hypocalcuria have been described in preeclamptic women. The urinary calcium excretion increase during normal pregnancy is attributed either to increased GFR and decreased tubular reabsorption of Ca, or to dissociation between Na and Ca tubular handling in the ascending loop of Henle. Contrary to normotensive women, preeclamptic patients have been shown to excrete less calcium

Some studies have foundreduced natriuria in preeclamp-sia propably related to the hypocalciuria process, because of renal involvement, reabsorption of sodium linked to calcium in the ascending loop of Henle has been described. The aim of this study was to assess the possibility of urinary calcium to creatinine and sodium to creatinine ratios as a marker in diagnosis.

At Obstetrics and Gynecology department in Ain Shams University a case control study was conducted on 135 women, Of those 90 patients were preeclamptic (45 diagnosed as mild and 45 diagnosed as severe) according to gold standard of PE diagnosis and 45 women as controls.

The exclusion criteria of this study were malnutrition, previous or gestational diabetes mellitus, renal diseases, previous significant proteinuria, super-imposed preeclampsia, continuous use of calcium supplement or calcium channel blocker, drugs that alter sodium level , multiple pregnancies.

All groups were subjected to: informative consent, detailed history, assessment of BMI, blood pressure was measured in a semi-recumbent position with a standard mercury sphygmomanometer, urine analysis of 24-h proteinuria and other urinary markers (calcium, sodium and creatinine) from a spot urine sample and ratios are calculated.

All data were statistically analyzed and tabulated and the result data showed that:

There was no statistical significant difference between control, mild and severe preeclampsia groups regarding maternal age, gestational age, parity and urinary creatinine.