To evaluate maternal, fetal, neonatal B-type natriuretic peptide (BNP) concentrations related to Intra Uterine Growth Restriction (IUGR). BNP concentrations in 43 IUGR and 35 healthy, Appropriate for Gestational Age (AGA) infants/paired mothers have been compared, from delivery/birth to first month of life. Maternal and IUGR cord BNP concentrations were coupled to fetal ultrasonography. Neonatal echocardiography was performed too. On delivery BNP was higher in all IUGR mothers, suffering or not from gestational hypertension, than in AGA (median 37.14 vs 11.1 pg/ml p=0.002). Maternal BNP was not associated to cord/neonatal BNP or fetal ultrasonographic parameters. Cord BNP was higher in IUGR than AGA newborns (median 23.9 vs 11.4 pg/ml p=0.0007) independently of gestational age, while varied with amniotic fluid (p=0.0044) and umbilical artery flowmetry (p=0.0121). Earlier drop of BNP on day 3 was reported in IUGR neonates (p=0.0001).Ventricular mass change/body weight varied positively in AGA newborns (p<0.001), while declined in IUGR ones (p=0.003). Carrying IUGR fetus is a stress factor resulting in high maternal BNP concentration. Altered fetal ultrasonographic parameters in IUGR newborns lead to higher BNP cord levels. A rapid BNP drop and probable ventricular mass adjustment of IUGR newborns may indicate earlier post-natal cardiovascular adaptation than AGA infants.