The effects of chronic ethanol consumption during early pregnancy on conceptus health and uterine function in pigs.

Background: Maternal ethanol consumption impairs fetal health, but it is unclear if this occurs through direct actions on the conceptus or indirectly through effects on the uterus. The objective of this study was to determine if chronic ethanol consumption in swine would impair early embryonic and fetal health either through direct effects on the conceptus or indirect effects on the endometrium.

Methods: Four experiments evaluated the effects of chronic ethanol consumption during early pregnancy. Female pigs were fed either 350 ml of 95% ethanol or an isocaloric amount of dextrose at 10 to 14-hr intervals beginning on day 10 after pubertal estrus and continuing until ovariohysterectomy 11 to 35 days after mating. At the second estrus, pigs were mated to a fertile boar that did not consume alcohol.

Results: In experiment 1, ethanol consumption increased (p < 0.01) blood alcohol concentrations that peaked 2-3 hr after feeding. In experiment 2, ethanol was detectable in uterine flushings 2 hr after feeding on day 11 of pregnancy and was highly correlated (r = 0.989, p < 0.001) with blood alcohol concentration. In experiment 3, ethanol consumption did not affect endometrial phospholipase C activity on days 11 and 16 of pregnancy but decreased (p < 0.05) basal endometrial prostaglandin F(2alpha) production on day 16. However, ethanol consumption did not decrease the number of conceptuses on day 11 or conceptus DNA content on days 11 or 16. In experiment 4, ethanol consumption decreased (p < 0.05) fetal survival rate to 58% versus 85% in dextrose-fed controls on day 35 of pregnancy. For viable conceptuses, ethanol consumption reduced (p < 0.01) fetal weight, fetal crown-rump length, placental weight and volume of placental (chorio-allantoic + amniotic) fluid.

Conclusion: These results indicate that chronic ethanol consumption may impair conceptus health directly or indirectly through actions upon the endometrium. Thus, the pig may be a valuable experimental model for studies on the effects of maternal alcohol consumption on conceptus development.