It happens every day: a woman discovers she's pregnant, then remembers with dread the cocktails she consumed the week before. According to a new study, she can probably breathe easy, but she should focus most of her caution on the second half of pregnancy, when alcohol does the most damage.
John W. Olney, a neuropsychopharmacologist from Washington University in St. Louis, found that alcohol accelerates a natural process called neuroapoptosis, which causes developing neurons to "commit suicide" if they fail to connect on schedule with neighboring brain cells. Alcohol slows the rate at which connections are formed, fooling cells into believing they've failed to make contact. Olney reported his findings at a meeting of the American Association for the Advancement of Science.
Working with mice, Olney found that as little as one hour's exposure to blood alcohol levels of 0.06 to 0.08 percent—just below the legal driving limit in most states—substantially increases the death rate of developing brain cells. Humans, most likely, would be similarly affected. "Over the millennia, alcohol has damaged more fetal brains than any other agent in the human environment," Olney says.