NT-proBNP: A Biochemical Marker of Maternal Complications in Pre-eclampsia

Abstract

Introduction: Elevated serum levels of NT-proBNP (N terminal pro-Brain Natriuretic Peptide) are associated with Pre-Eclampsia (PE) and its complications. Aim: To evaluate NT-proBNP in women with PE and correlate its levels with maternal outcome. Materials and Methods: A total 90 out of which 45 women with PE (Group A) and 45 normotensive healthy pregnant women with singleton pregnancy (Group B) were enrolled. NT-proBNP was estimated at term or just before induction of labour or in early labour. These women were followed till 48 hours postpartum. Maternal outcome was recorded and analysed using statistical tests like Student t-test, Mann-whitney, ANOVA, Kruskal Wallis, Pearson and Spearman correlation. Results: Significant elevated serum levels of NT-proBNP were seen in PE women than controls (mean 439.47±431.99 and 99.40±37.89 respectively) (p-value <0.001). Severity and early onset of PE was associated with further increased serum NTproBNP levels. In Group B none of the women developed any complication whereas, in Group A 19/45 (42.22%) women had a total of 31 complications. Forty percent of these PE women had maternal complications and elevated NT-proBNP levels above 500 pg/mL. Cardiovascular complications were observed in 4/45 women with NT-proBNP levels of 770 pg/mL and above. The positive predictive value for NT-proBNP for detecting complications was 83.33% at a cut-off level of 500 pg/mL. The negative predictive value was 92.85% at a cut-off level of 100 pg/mL. Women in Group A with early onset PE, who did not develop maternal complications, had low serum NT-proBNP. Women without severe features of PE (n=12) in Group A who developed complications, had elevated NT-proBNP (mean 434±307.219 pg/mL) than those who had no complication (mean NT-proBNP 80.66±37.54 pg/mL). Conclusion: NT-proBNP is a useful marker for predicting maternal complications and risk stratification for optimum maternal outcome in a PE women.

Keywords

• hypertensive disorders
• maternal complications
• n terminal pro-brain natriuretic peptide