Perinatal changes of circulating N-terminal pro B-type natriuretic peptide (NT-proBNP) in normal and intrauterine-growth-restricted pregnancies.

Objective: To investigate changes in NT-proBNP in intrauterine-growth-restricted (IUGR) and appropriate-for-gestational-age (AGA) pregnancies. Methods: NT-proBNP levels were measured in 40 mothers (MS), umbilical cords (UC), and their 20 IUGR/ 20 AGA neonates on day 1 (N1) and day 4 (N4). Results: UC, N1, and N4 NT-proBNP was lower in IUGR pregnancies (p ≤ 0.049). In both groups, NT-proBNP levels were similar in MS and higher in N1 (p ≤ 0.001). In AGA, MS NT-proBNP correlated positively with UC. Conclusions: Fetal and neonatal NT-proBNP levels are lower in IUGR compared with AGA, probably due to blood flow redistribution in IUGR and NT-proBNP placental transport in AGA. NT-proBNP levels peak on N1.