On the night of my 32nd birthday, my husband and I enjoyed a delicious dinner while on vacation in Orvieto, Italy. To complement my pasta, I drank a single glass of red wine, my first since learning I was pregnant four months earlier. Even now my indulgence that evening inspires periodic pangs of guilt: Did I stunt my son's potential by sipping that Sangiovese?

Nobody questions the notion that heavy drinking during pregnancy is harmful. It can cause facial abnormalities, central nervous system problems and stunted growth. But evidence regarding the effects of light or occasional drinking is mixed. In five epidemiological studies published in 2012, medical psychologist Erik Mortensen of the University of Copenhagen and his colleagues found that five-year-old children born to women who had one to four drinks a week during pregnancy displayed no deficits in general intelligence, attention or other types of higher-order thinking. On the other hand, in 2011 psychiatrist Nancy Day of the University of Pittsburgh and her colleagues reported that teens born to women who averaged more than one drink a week during pregnancy were twice as likely as those born to nondrinkers to have conduct disorder, a condition characterized by theft, deceit or violence.

The truth is hard to discern because research on the issue is fraught with problems. The ideal type of experiment is not ethical: scientists cannot randomly assign one group of women to drink during pregnancy and compare the outcome with those instructed to abstain. As a result, they must compare what happens to women who choose to drink during pregnancy with those who do not, and these women often differ in important ways. All things considered, having an occasional drink during those nine months—say, one or two a week—probably poses little, if any, harm. Still, some experts warn, light or sporadic drinking may have effects we do not know how to measure.

Messy Methodologies

The thorniest problems with this research involve the ways in which women who drink during pregnancy differ from those who do not. A woman who drinks moderately or heavily is more likely to smoke, use drugs and physically abuse her child than a nondrinker, all of which could worsen her son's or daughter's prognosis independent of alcohol. This woman might also have a genetic background predisposing her—and her children—to behavioral problems.

Meanwhile women who drink lightly while pregnant may have protective characteristics. Compared with abstainers, they “are often the more affluent moms, the more educated moms, and the smarter moms as well,” perhaps because they belong to a higher socioeconomic class than teetotalers, says epidemiologist Ron Gray of the National Perinatal Epidemiology Unit at the University of Oxford. This effect could explain why, in a 2010 study, clinical psychologist Monique Robinson and her colleagues at the Telethon Institute for Child Health Research in Perth, Australia, discovered that children of mothers who drank two to six drinks a week while pregnant were less likely to have behavioral problems in the first 14 years of their lives than were children of mothers who abstained. As with most such studies, the researchers tried to account for systematic differences in the groups, but as Robinson acknowledges, “these unmeasured factors may have influenced our results.”

Another complexity: most studies assess maternal drinking through interviews, and pregnant women might lie about or underestimate their consumption out of embarrassment or shame. Lower estimates can mask harmful effects if they cause light drinkers to be incorrectly categorized as abstainers and put in the comparison group. They might, however, inflate the perceived risk if heavy-drinking mothers of children with deficits get incorrectly categorized as light drinkers.

4 Comments

1. 1. jimmywat 01:44 AM 2/14/13

   http://tinyurl.com/4l4tpu3
   No amount of alcohol is ever safe for anyone. And this article points out the addiction of even expecting mothers. Why is it so important that she have a drink? She has all the things that are safe, that are good for her and taste good (alcohol does not taste good - watch a child try it for the first time. Of course the wine addicts claim that wine tastes good, but take a big slug of it and see if you don't choke!)

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2. 2. fixerdave in reply to jimmywat 04:07 AM 2/14/13

   http://www.scientificamerican.com/article.cfm?id=moderate-drinkers-less-li
   
   "... have found that it may help some people survive after heart attacks."
   
   There are others on SA but they're now paid... so no point quoting them. Lots of other info on the web, but I'll be nice to SA.
   
   http://www.scientificamerican.com/blog/post.cfm?id=in-us-fewer-die-of-heart-disease-bu-2008-12-16
   
   "The bad news: heart disease is still the nation’s top killer"
   
   Sorry, you're wrong. We have evidence that moderate drinking reduces heart disease (much stronger evidence that it causes harm) and heart disease is a rather significant risk. Top of the list, actually. Balancing the gains verses risk for pregnant women is an important question.

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3. 3. vmfenimore 07:24 AM 2/14/13

   Oh you poor dear. You dared to broach the taboo of drinking any alcohol while pregnant and actually admitted to a glass of wine while pregnant. The hate messages you are going to receive.
   
   I discovered while pregnant that there were a ton of dietary rules I was supposed to follow. I should eat right, exercise, not drink, etc.... Yet when I complained about pitting edema and my resting heart rate doubling ... "well there there dear, you're ok to work full time while only being physically able to rest 4 hours a night because you're so uncomfortable". No one seemed to take seriously that I was so out of breath (while SITTING) that I had to sneak out of the office to a restroom with a cot behind a screen and lay down so that I could breathe. Luckily I had a co-worker who covered for me.
   
   And geez my baby was born early. I was the only one not surprised because I knew my body could not take it anymore.
   
   If all the pregnancy experts would shut up about diet and promote reduced work hours for people in their third trimester and a policy that allows for women to start their maternity leave before they start their labor, I bet we would see more babies carried to term and healthier newborns. My German cousin was BRAGGING how she was still working part time at 38 weeks. Um try working until you start labor. And finish that task before driving to the hospital.
   
   But God forbid you have a glass of wine. Because there is no chance it will lower your stress during a time when people are expecting way too much from you physically.
   
   The way we treat pregnancy and maternity leave in the Country is such BS. Try searching the web and reading advice given to pregnant women in other countries. It's much more gentle. (ex. I read a UK advice column that recommended asking your employer if you could arrive late every day and leave early). Oh and they have lower infant mortality rates.
   
   I say have that drink (that ONE) drink. And take a load off.
   
   

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4. 4. jmtepper in reply to jimmywat 07:31 AM 2/14/13

   Sorry jimmywat. The many pejoratives in your comment indicate that pregnant or not, you are what they used to call a teetotaler. You seem to think that all drinking is an addiction. It is not, and occasional drinking (especially of red wine) is not only not harmful, but probably beneficial.
   
   The idea that a glass of wine every now and again is harmful during pregnancy seems to be almost an uniquely American concept. It's ridiculous. In many European countries, wine is imbibed routinely at dinner. Even by pregnant women. Doesn't seem that there is a greater incidence of negative alcohol-related effects in Europe compared to the US. Interesting also, that the Copenhagen Study found no deleterious effects of even moderate drinking during pregnancy, while the US Study did.

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