Stress physiology in neonates after nicotine exposure during pregnancy

Introduction: There is evidence that fetal nicotine exposure during pregnancy may have an influence on the development of the hypothalamo-pituitary-adrenal (HPA) axis. We analyzed cortisol and cortisone stress response patterns in neonates from smoking mothers and controls. Methods: Saliva samples of 16 healthy nicotine exposed (5–30 cigarettes / day during the whole pregnancy) neonates >34 weeks of gestation were collected before and after a painful stress event at the 3rd day of life and analyzed for cortisol and cortisone levels. 40 healthy infants of non-smoking mothers served as controls. Results: Infant birth weight percentiles and gestational age at delivery were comparable between study and control infants. Median baseline levels of cortisol and cortisone were not significantly different in control and study infants (p=0.1328, p=0.2091, respectively). In control infants, cortisol and cortisone levels significantly increased 20 minutes after the stress event. In contrast, stress reaction in infants with intrauterine nicotine exposure was noticeably suppressed. ANOVA confirmed the different reaction between control and study infants indicating a significant reaction over time in controls (p<0.05) as opposed to the study group (p=0.1340). Conclusion: Our preliminary results suggest that neonates of mothers that have been smoking during pregnancy have an altered reaction of the cortisol system in response to a stress event at the 3rd day of life. Alterations of the HPA axis, if they persist, may entail long-term consequences for the health of these infants in later life.

cortisol - intrauterine - nicotine - stress physiology