Amino-terminal pro-brain natriuretic peptide in normal and hypertensive pregnancy

Objectives: To investigate serum levels of amino-terminal pro-brain natriuretic peptide (Nt pro-BNP) as an index of left-ventricular function in normal pregnancy and pregnancies complicated by hypertension and also to investigate levels in both primigravid and multigravid women. Methods: Women with hypertension in pregnancy (at least two readings of systolic blood pressure > 140 mm Hg and diastolic blood pressure > 90 mm Hg) (n = 24) and normotensive women (n = 42) were included in the study. Serum Nt pro-BNP was measured using an enzyme-linked immunosorbent assay technique. Results: The median serum Nt pro-BNP level in pregnancies complicated by hypertension was 420 fmol/L, which was significantly greater than that measured in samples obtained from normotensive women in pregnancy (340 fmol/L) (p = 0.03). There was a nonsignificant trend toward increased levels in proteinuric as compared to nonproteinuric hypertension in pregnancy. Multigravida had higher Nt pro-BNP levels (n = 26; median Nt pro-BNP = 358 fmol/L) than primigravida (n = 16; median Nt pro-BNP = 278 fmol/L) (p = 0.01) in association with normal pregnancy. Multigravida also demonstrated a dramatic rise in serum Nt pro-BNP levels in association with hypertension in pregnancy (n = 13; median Nt pro-BNP = 572 fmol/L) as compared to normal pregnancy (n = 26; median Nt pro-BNP = 358 fmol/L) (p = 0.009). Conclusion: Serum Nt pro-BNP is elevated in women with hypertensive disorders of pregnancy, indicating elevated left-ventricular filling pressures. Measured serum levels in both normal and hypertensive pregnancy are higher in multigravida than in primigravida.