Association of NT-proBNP with plasma renin activity and plasma aldosterone concentration in women with singleton pregnancy.

OBJECTIVE: To determine the association of the N-terminal fragment of precursor protein brain-type natriuretic peptide (NT-proBNP) levels with plasma renin activity (PRA) and plasma aldosterone concentration (PAC) in singleton pregnancies.

DESIGN: Serum NT-proBNP levels, PRA and PAC were determined in 215 blood specimens from 139 women with singleton pregnancies, including 34 and 105 women who did and did not develop hypertensive disorders in pregnancy, respectively. Twenty-five blood specimens were obtained from 25 women who later developed hypertension (systolic BP⩾140mmHg and/or diastolic BP⩾90mmHg), but were normotensive at the time of blood sampling.

RESULTS: The serum NT-proBNP levels [pg/ml, median (range), 32 (5-142)] did not change in normotensive women, but increased significantly to 97 (23-436) after the development of hypertension (D/H). The PRA [ng/ml/h, median (range), 7.1 (1-20)] did not change in normotensive women, but decreased significantly to 1.9 (1-16) after D/H. PAC (pg/ml) increased significantly from 397 (94-1750) to 667 (123-2010) between the 2nd and 3rd trimesters in normotensive women. However, as PAC of hypertensive women did not change significantly before and after D/H, PAC [293 (116-1720)] after D/H was significantly lower than that [667 (123-2010)] of the 3rd trimester in the normotensive women. The serum levels of NT-proBNP were significantly and negatively correlated with both PRA and PAC.

CONCLUSIONS: The renin-angiotensin-aldosterone system is suppressed in pregnant women with cardiac conditions associated with higher NT-proBNP levels.