High copeptin concentrations in umbilical cord blood after vaginal delivery and birth acidosis

CONTEXT: The pituitary-secreted nonapeptide arginine-vasopressin (AVP) is unstable and therefore unsuited for diagnostic use, but its secretion can be estimated by measuring copeptin, the C-terminal portion of the AVP precursor (pro-AVP). OBJECTIVE: Our objective was to investigate perinatal factors affecting copeptin concentrations in infants at birth and at 3 d of life. DESIGN AND SETTING: We conducted a prospective cross-sectional study at a tertiary university hospital. PATIENTS: Copeptin plasma concentrations were evaluated in 177 infants at birth, including 117 paired arterial/venous umbilical cord and 102 venous blood samples obtained at 3 d of life. MAIN OUTCOME MEASURE: Copeptin concentrations were determined by a C-terminal pro-AVP luminescence immunoassay. RESULTS: Arterial umbilical cord copeptin concentrations were consistently higher than matched venous ones (median 18 vs. 10 pmol/liter, P < 0.001), but both values were closely related (R(s) = 0.825; P < 0.001), and both were negatively related to arterial umbilical cord pH (R(s) arterial/venous = -0.578/-0.639; P < 0.001). Although exceedingly high copeptin concentrations were observed after vaginal birth in umbilical cord arterial [median (5-95% range) = 1610 (85-5000) pmol/liter] and venous [793 (6-4836) pmol/liter] plasma, copeptin concentrations were low after primary cesarean section [arterial/venous = 8 (3-907)/5 (5-504) pmol/liter]. Postnatal body weight loss was associated with increased copeptin concentrations at d 3 (R(s) = 0.438; P < 0.001) and was inversely related to copeptin concentrations at birth (R(s) = -0.289 and -0.309; both P = 0.001). CONCLUSION: Vaginal birth is associated with a large release of copeptin that exceeds all values published so far, including those in critically ill adult patients with shock or brain injury. Thus, vaginal birth is arguably the most intense stressor in life

Plasma midregional proadrenomedullin in newborn infants: impact of prematurity and perinatal infection

INTRODUCTION: Adrenomedullin (ADM) is one of the strongest endogenous vasodilating hormones. Its stable by-product midregional-proADM (MR-proADM) is an established indicator of systemic infection and cardiovascular compromise in adult patients. METHODS: A prospective cross-sectional study was performed to investigate the perinatal factors affecting MR-proADM plasma concentrations in 328 newborn infants with a gestational age (GA) between 24 and 41 wk. RESULTS: Blood samples were obtained in 270 infants from umbilical veins (with additional 108 paired samples from umbilical arteries), and at 2-3 d of life in 183 infants. Paired venous and arterial umbilical cord MR-proADM concentrations were closely related (Spearman's rank order correlation coefficient (R(s)) = 0.825, P < 0.001). MR-proADM concentrations at birth and at 2-3 d were inversely related to GA (R(s) = -0.403 and R(s) = -0.541, respectively) and birth weight (BW; R(s) = -0.421 and R(s) = -0.530, respectively; all P < 0.001). On stepwise regression analysis, clinical chorioamnionitis and umbilical arterial blood base excess retained a significant impact on MR-proADM cord venous blood concentrations. At 2-3 d of life, histologic chorioamnionitis and GA at delivery were significantly associated with MR-proADM levels. DISCUSSION: As compared with adults, MR-proADM concentrations are elevated in neonates, especially those born very preterm. Immaturity and infection, which both feature low systemic vascular resistance, are related to increased MR-proADM concentrations