From the standpoint of popular culture, drinking during pregnancy is the equivalent of playing Russian roulette with your fetus. Any woman daring to consume a single glass of wine in public risks being construed as the most unnaturally selfish of mothers. Even as recent studies suggest that science refuses to conclude the case, we cling to the prohibition in a way that precludes discussion. But perhaps that shouldn't be surprising—our reasons may have as much to do with the distinctive morality of pregnancy as they do with science.
This month the issue was revived again. A new study out of Great Britain found that the 5-year-old children of moms who consumed up to two drinks a week appeared to do no worse on tests of behavior and cognition than the children of mothers who abstained. Indeed, in some tests— in vocabulary, for instance—the boys of light drinkers did better than the boys born to abstainers. A study published this spring out of Australia found something similar: The children of women who drank in relatively small amounts early in pregnancy appeared to demonstrate fewer behavioral problems than the children of those who abstained during the same period. The Australian researchers wondered, controversially, whether light drinking might help relax the mothers, yielding better kids.
Which made me wonder why the teetotaling counsel that American women get during pregnancy is so stern and unyielding. We've known for close to 40 years that some children of mothers who drink heavily during pregnancy will be born with fetal alcohol syndrome. But for smaller amounts of alcohol, the picture is far less clear. In the absence of certain proof of harmlessness, the American dogma goes, abstain. But what if small amounts of alcohol consumption are fine or even beneficial? Why doesn't the medical community make clear what they know for sure and what they don't, and let women decide for themselves?
Trying to understand the research on drinking while pregnant is a bit like examining a pointillist painting—the image dissolves into meaningless dots the more closely you examine it. Since researchers can't treat pregnant women like rats—keeping them in a lab, feeding them alcohol—it can be difficult to distinguish causation from correlation. For instance, the researchers who conducted the British study admitted that their light drinkers were of higher socioeconomic status than their abstainers, and suggested this might explain some of the disparity in how children did on various tests. Not only that, but as University of Washington fetal alcohol syndrome researcher Susan Astley pointed out to me, the British study looked at children only at the age of 5. Yet a link between alcohol and developmental problems in higher order thinking might not become obvious till a few years later. Plus, Astley observes, the study found little damage even in children of heavy drinking moms—a curious outcome that makes her wonder if its methodology is flawed. Several criticisms can also be leveled at the Australian study.
There is also a good deal of research going in the other direction, as science writer Annie Murphy Paul explains in her new book, Origins. According to this work, "even moderate drinking during pregnancy is associated with behavior, learning, and attention problems in offspring." Another wrinkle in interpreting the conflicting studies is that yet more studies suggest that risk factors like poverty, smoking, advanced maternal age and even genetic vulnerability may exacerbate the effects of alcohol consumption in the womb. And one more twist: It appears to matter when during pregnancy a woman drinks and how much she drinks in one sitting.
In other words, any two women, and any two fetuses, are not the same, even if they have consumed the same overall amount of alcohol during a nine-month period. All of these permutations make it difficult to conclude what amount of alcohol might cause problems for an individual fetus. So researchers cannot agree on a generally permissible upper limit. "There is no known safe amount of alcohol to drink while pregnant," as the CDC puts it.
This is why an obstetrician will warn patients not to consume any alcohol whatsoever, but tell a particular panicked woman who reports drinking twice before she realized she was pregnant that her baby is fine. "I will strongly suggest to women who plan pregnancy that they don't drink," says Gideon Koren, who directs a clinical, research and teaching program called Motherisk at the Hospital for Sick Children in Toronto. After all, Koren says, lack of proof of harm does not equal lack of harm. And alcohol is not like asthma medication, worth some risks because of benefits to the mother's health.But that doesn't mean he expects the babies of women who drink a bit to be harmed by it.