Fetal and maternal sheep hypothalamus pituitary adrenal axis responses to chronic binge ethanol exposure during the third trimester equivalent

Background: We tested the hypothesis that in utero ethanol exposure results in changes in fetal and maternal adrenocorticotropin (ACTH) and cortisol during the third trimester equivalent, by using a chronically instrumented fetal sheep model. Methods: Pregnant ewes received saline or ethanol intravenously 3 consecutive days per week from day 109 to day 132 of gestation. Fetal and maternal blood samples were collected on days 118 and 132. Results: Maternal and fetal ACTH and cortisol values increased on days 118 and 132 of gestation in response to ethanol infusions that created blood ethanol concentrations (BECs) that are easily achievable by human drinkers. Peak ACTH and cortisol values were detected 30 to 60 min after peak BECs were achieved. Conclusions: Chronic ethanol exposure during the third trimester equivalent in sheep resulted in repeated activation of the hypothalamus-pituitary-adrenal axis in both the mother and fetus. Temporally, the patterns of maternal and fetal responses to ethanol infusion were similar. We conclude that ovine maternal ethanol exposure during the third trimester equivalent increases fetal ACTH and cortisol concentrations, hormonal responses that may play a role in mediating alcohol-related birth defects.