Blunted stress response in small for gestational age neonates.

There is evidence that adverse conditions during intrauterine development affect future health of the offspring. Hypothalamus-pituitary-adrenal (HPA) axis dysregulation is assumed to play an important role in the association of small for gestational age (SGA) and the pathogenesis of hypertension and the metabolic syndrome. Stress response patterns in SGA neonates may identify a link with intrauterine-induced permanent maladaptation of the HPA axis. Salivary cortisol and cortisone levels were therefore analyzed during resting conditions and in response to a pain-induced stress event in SGA (<5th percentile) and appropriate for gestational age (AGA) neonates born > or =34 wk of gestation. In AGA neonates, salivary cortisol and cortisone levels significantly increased after the stress event (p < 0.05). In contrast, SGA infants exhibited a blunted steroid release after stress induction (p = 0.76, p = 0.65, respectively). No influence of mode of delivery (p = 0.93), gender (p = 0.21), and gestational age (p = 0.57) on stress response patterns was observed in a multiple stepwise regression. SGA neonates show a blunted physiologic activation of the HPA axis in response to a stress stimulus. Thus, intrauterine-induced alteration of HPA axis regulation seems to persist into the postnatal period and represents a prerequisite for the hypothesis of HPA axis involvement in the fetal origin of adult diseases.