Many fans of TV's "Mad Men" marveled during Season 3 as Betty Draper, heavily pregnant, drank just as much alcohol as she did before she was expecting.
How pregnant women treat their bodies, along with their unborn children, has changed drastically since the mid-60s. For the last few decades, expectant mothers were told to abstain from alcohol completely until they gave birth.
And for good reason. Abstaining from alcohol is obviously the best way to avoid alcohol-related birth defects (ARBD) in fetuses. And studies show excessive consumption of alcohol during pregnancy adversely affects the fetus, and could lead to very severe developmental or other problems in the child.
But what about one small drink, every once in a while? Does that harm a fetus? Up until recently, the consensus was yes - that it was downright child abuse.
However, studies are slowly coming in that show unborn children are barely affected by occasional or light drinking by the mother during pregnancy. If at all.
A large population-based observational study from the United Kingdom found that at the age of five years, the children of women who reported light (no more than 1-2 units of alcohol per week or per occasion) drinking did not show any evidence of impairment on testing for behavioral and emotional problems or cognitive ability.
Interestingly, while there was a tendency for the male children of women reporting "heavy/binge" drinking during pregnancy (7 or more units per week or 6 or more units per occasion) to have poorer behavioral scores, the effects were less clear among female offspring.
A second study, published in Pediatrics, based on a group of Western Australian women examined the associations between dose, pattern, and timing of prenatal alcohol exposure and birth defects. It found similar results to the UK study -- there was no association between low or moderate prenatal alcohol exposure and birth defects.
In the study, information about maternal alcohol consumption was collected from a randomly selected, population-based group of Western Australian women who gave birth to a live infant between the years of 1995 and 1997.
The information was collected three months after birth for the three month period before pregnancy and for each trimester separately.
The study broke the women down into four categories: women who abstained from drinking alcohol while pregnant, women who drank a little (70g of alcohol or less per week), "heavy drinkers" (more than 70g a week), and "very heavy drinkers" (more than 140g a week).
Not surprisingly, the babies born to the "heavy drinkers" and "very heavy drinkers" were more likely to have ARBD.
But the babies born to women who had an occasional drink during their pregnancy were no more likely to have ARBD than the babies born to mothers who abstained from alcohol completely.
This is not to say that all pregnant women can belly up to the bar.
Socio-economic, education, and other lifestyle factors of the mother have large effects on the health of the child, both in utero and out in the world. These must be considered when evaluating the potential effects of consuming alcohol during pregnancy.
