Pregnancy in a healthy population: dynamics of NTproBNP and hs-cTroponin T

Abstract

ObjectiveTo describe the intraindividual changes of heart biomarker levels during and after pregnancy and to evaluate existing cut-off levels for heart failure or myocardial ischaemia in pregnant women.MethodA total of 196 healthy pregnant women were recruited from maternal outpatient clinics and included in the study. Blood samples were obtained on four occasions: at 10–12 gestational weeks (gw), 20–25 gw, after delivery and 6 months postpartum and analysed for N-terminal pro-brain natriuretic peptide (NTproBNP) and high sensitive cardiac troponin T (hs-cTNT). Echocardiography ruled out existing cardiac disease. Estimated glomerular filtration rate (eGFR) was calculated.ResultsThere were significant changes in NTproBNP between the measurements with the highest NTproBNP at 10–12 gw and the lowest value being at 20–25 gw, (with eGFR being the highest). Hs-cTNT was significantly higher at the peripartum measurement compared with the other measurements (p<0.05). Regardless, the 95th percentile for both biomarkers was below cut-off levels of 300 ng/L for NTproBNP and 14 ng/L for hs-cTNT. There was an association between NTproBNP above the upper limit of normal of 125 ng/L and eGFR (p=0.04) and between hs-cTNT >5.0 ng/L and time from delivery to blood sample (p=0.001) at the peripartum measurement. Both were associated with the use of oxytocin.ConclusionExisting cut-off values for ruling out heart failure (NTproBNP <300 ng/L) and myocardial ischaemia (hs-cTNT <14 ng/L) are applicable during pregnancy and after delivery. Elevated levels mandate further attention on cardiac symptoms and renal function.