Should you worry about that New Year's Eve sip of bubbly?

Many women entirely abstain from alcohol during pregnancy and worry about the possible fetal effects of any alcohol they consumed before they knew they were pregnant. Their caution and concern may seem well-placed; studies that show that excess alcohol consumption during pregnancy can cause low birth weight, cognitive impairment, behavioral problems, or even full-blown fetal alcohol syndrome.  The effects of heavy drinking during pregnancy are uncontroversial and are very serious to the health of the developing fetus, not to mention that anyone with binge drinking tendencies or a bottle-of-Jack-per-week habit is obviously ill-suited to be a parent for other reasons. 

If heavy drinking causes serious effects, doesn't it make sense to assume that even light drinking has some detrimental effects?  In short, no.  Obviously, the fact that excessive ingestion of any substance can have serious consequences doesn't necessarily mean that there are any risks to occasional, moderate ingestion of the same substance.  For example, although cyanide is lethal in sufficient doses, no one swears off eating apples because their seeds contain trace amounts of cynaide - the amount found in the seeds is so insignificant that accidentally swallowing the seeds has absolutely no detrimental effect. 

Thus, it is perhaps not surprising that new medical research shows that light drinking during pregnancy - i.e. having 1 or 2 drinks per week - has no discernible affects on your developing baby.  Researchers followed the children of women with different drinking habits (those who abstained entirely during pregnancy, those who had 1-2 drinks per week and those who were heavier drinkers) until the children were 5 years old, and found that light drinking during pregnancy had absolutely no detrimental effect on children's cognitive abilities or behavioral tendencies.  (Light drinking by the mothers at first actually seemed to have beneficial cognitive and behavioral effects on their children, until researchers controlled for the income and education levels of the mothers.)

For a decent layperson's summary of the study, click here.  To read the abstract and access a link to the full text of the study, in all its technical detail, click here. (Note: the full text of the study can only be accessed through a university library or with some other kind of subscription to the Journal of Epidemiology and Community Health.)

In short, the problem with studies of the fetal effects of the consumption of just about anything during pregnancy is that they tend to focus on pregnant women who ingest a lot of the substance. This makes it difficult for pregnant women to know what commonly ingested foods and medicines may be entirely safe in moderation.  This kind of study, with its focus on moderate alcohol consumption, is thus a valuable find (even if it is, unfortunately, retrospective regarding pregnant women's alcohol consumption).  It finds no evidence that light alcohol consumption during pregnancy causes any harm to the developing fetus, so have a glass of wine on date night if you'd like, and don't sweat that New Year's Eve toast!