B-type natriuretic peptide in pregnant women with heart disease.

OBJECTIVES: The objectives of this study were to examine: 1) B-type natriuretic peptide (BNP) response to pregnancy in women with heart disease; and 2) the relationship between BNP levels and adverse maternal cardiac events during pregnancy.

BACKGROUND: Pregnancy imposes a hemodynamic stress on the heart. BNP might be a useful biomarker to assess the ability of the heart to adapt to the hemodynamic load of pregnancy.

METHODS: This was a prospective study of women with structural heart disease seen at our center. Serial clinical data and plasma BNP measurements were obtained during the first trimester, third trimester, and after delivery (>6 weeks).

RESULTS: Seventy-eight pregnant women were studied; 66 women with heart disease (age 31 ± 5 years), and 12 healthy women (age 33 ± 5 years). During pregnancy, the median peak BNP level was higher in women with heart disease compared with control subjects (median 79, interquartile range 51 to 152 pg/ml vs. median 35, interquartile range 21 to 43 pg/ml, p < 0.001). In women with heart disease, those with subaortic ventricular dysfunction had higher BNP levels (p = 0.03). A BNP >100 pg/ml was measured in all women with events during pregnancy (n = 8). Sixteen women had increased BNP levels during pregnancy but did not have clinical events. None of the women with BNP ≤100 pg/ml had events. BNP ≤100 pg/ml had a negative predictive value of 100% for identifying events during pregnancy.

CONCLUSIONS: Many pregnant women with heart disease have increased BNP levels during pregnancy. Incorporating serial BNP levels in into clinical practice can be helpful, specifically in adjudicating suspected adverse cardiac events during pregnancy.