Infant stress reactivity and prenatal alcohol exposure.
BACKGROUND
Animal studies have shown that prenatal alcohol exposure (PAE) is linked to alterations in the stress response systems. To date, little is known about the impact of PAE on stress systems in human infants. The current study examined PAE effects on the stress response, as evidenced by the activation of the limbic-hypothalamic-pituitary-adrenal (L-HPA) axis and autonomic system and changes in negative affect during a social-emotional challenge in human infants. We also examined whether the effects of PAE on infant responsiveness differed in boys and girls.


METHODS
Measures of cortisol, heart rate, and negative affect were obtained during a modified version of Tronick's still-face procedure, a standardized developmental paradigm used to study emotion and stress regulation. Our sample included fifty-five 5- to 7-month-old infants whose mothers were enrolled in an alcohol intervention study. Measures of maternal alcohol consumption during pregnancy and after delivery were obtained using Timeline Followback interviewing methods. Relationships between prenatal alcohol consumption and infant outcomes were examined. In addition, mothers were divided into high and low-frequency drinkers, based on the mean percent of prenatal drinking days (PDD) to facilitate between-group comparisons of infant stress measures.


RESULTS
Mothers enrolled in our study reported significant reductions in alcohol consumption after learning of their pregnancies. Nevertheless, PDD from conception to pregnancy recognition was related to increases in cortisol reactivity, elevated heart rate, and negative affect in their infants. The effects of PAE on infant responsiveness were significant after controlling for the effects of maternal depression and annual income. In addition, the effects of PAE on cortisol reactivity differed for boys and girls.


CONCLUSIONS
Greater PAE was related to greater activation of stress response systems. Our findings suggest that PAE affects the development of infant stress systems and that these effects differ in boys and girls. This work supports the possibility that PAE is related to alterations in infant stress systems, which could underlie problems in cognitive and social-emotional functioning that are common among persons exposed prenatally to alcohol.
Haley
David W
DW
Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada. haley@utsc.utoronto.ca
Handmaker
Nancy S
NS
Lowe
Jean
J
D000293:Adolescent; D000328:Adult; D000339:Affect / Q000187:drug effects; D000428:Alcohol Drinking; D001341:Autonomic Nervous System / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000009:adverse effects*; D002657:Child Development / Q000187:drug effects*; D000431:Ethanol / Q000009:adverse effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D007223:Infant; D008032:Limbic System / Q000187:drug effects; D008297:Male; D008425:Maternal Behavior; D010913:Pituitary-Adrenal System / Q000187:drug effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012107:Research Design; D012463:Saliva / Q000378:metabolism; D012727:Sex Characteristics; D012737:Sex Factors; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology*; D014481:United States
D002492:Central Nervous System Depressants; D000431:Ethanol; D006854:Hydrocortisone