THE BIOCHEMICAL ANALYSES OF PLASMA BRAINNATRIURETIC PEPTIDE, ALDOSTERONE, AND SODIUM LEVELS IN PATIENTS WITH PREECLAMPSIA IN BENIN CITY, EDO STATE, NIGERIA
Abstract
Background: Preeclampsia is a significant public health threat in both developed and
developing countries contributing to maternal and perinatal morbidity and mortality
globally.
Aim: The aim of the study was to determine the levels of Brain Natuiretic peptide,
Plasma and Urine Sodium, and Aldosterone in preeclamptic women and normotensive
pregnant women and the utility of these analytes as biomarkers for early detection of
preeclampsia.
Methodology: Ninety participants consisting of 45 preeclamptics and 45 normotensive
pregnant women were involved in the study. Preeclampsia was diagnosed as presence of
blood pressure of 140/90mmHg and above taken at least two occasions separated by six
hours and accompanied by significant proteinuria (300mg/L or 500mg/24hrs) in the
absence of a urinary tract infection in a previously normotensive woman. Venous blood
and spot urine were collected from participant for analysis. Brain Natriuretic peptide
(BNP) and aldosterone levels were analysed using ELISA Kits. Direct Ion selective
electrolyte analyzer was used in the analysis of plasma and urine sodium levels.
Results: The mean BNP levels of the preeclamptic women were significantly higher than
that of the normotensive pregnant women (795.8918.75 vs 350.0911.41, P=0.001).
Cross-tabulation between BNP and preeclampsia showed a sensitivity and specificity of
100% respectively in the first trimester participants, indicating absolute reliance of the
marker for predicting early onset of preeclampsia. The Reciever Operator Characteristic
curve (ROC) for BNP at first trimester also showed an area under the curve of 1.000,
with a suggested cut-off value of 558.46 pg/ml for making diagnosis. The mean plasma
sodium levels of the preeclamptics were significantly reduced compared to the
normotensive pregnant women (131.245.4 vs 136.425.82, P=0.001). There was
reduction in the mean aldosterone levels of the preeclamptics compared to the
normotensive pregnant women but however not statistically significant (254.0616.27 vs
301.586.22, P= 0.095).
Conclusion: The study showed increased plasma levels of BNP, reduced plasma sodium
levels and minimal reduction in aldosterone levels in preeclampsia. The study also
suggested that BNP could be relied upon as a diagnostic biomarker for predicting
preeclampsia, particularly during the first trimester. Regular measurement of plasma
BNP should be encouraged as a screening tool in assessment of patient at risk of
preeclampsia.
