On Tuesday (Feb. 2), the Centers for Disease Control and Prevention (CDC) issued a press release stating that over 3 million women in the US risk delivering babies with fetal alcohol spectrum disorders (FASD). The CDC recommends that women of child-bearing age who drink—regardless of whether or not they are trying to conceive—should be using birth control, which was a bit perplexing to say the least.
USA Today interpreted these recommendations to say that “young women should avoid alcohol unless using birth control.” The Washington Post called the recommendation “incredibly condescending.” The Atlantic points out that the recommendations suggest “women have no knowledge of or control over their own fertility.”
The CDC estimates 1 in 20 are born with some form of FASD, which can cause cognitive impairment and in more severe cases, problems with muscle coordination and facial abnormalities.
Though heavy drinking while pregnant—especially in the early stages of gestation—may cause FASDs, the effects of a few drinks are murkier. Emily Oster, an economist and author of Expecting Better: Why the Conventional Pregnancy Wisdom Is Wrong—and What You Really Need to Know, said that according to the scientific literature, occasional drinking during pregnancy may not have health consequences.
“We have a lot of studies which cover occasional light drinking, by which I mean a couple of light drinks a week in the first trimester, and a couple of drinks per day in the second and third trimester,” she told Quartz, “And those studies show no adverse effects in those behaviors. In fact, it’s basically impossible to find a well-run study which shows any negative impact of drinking at that level.”
The CDC statement, however, does not allude to this uncertainty.
David Spiegelhalter, a statistician specializing in risk communication at Cambridge, told Quartz in an email: “It’s worth looking at the CDC’s statement carefully. They say (a) that any drinking puts a woman at risk for an alcohol-exposed pregnancy [and] (b) alcohol can permanently damage a baby. Both these statements are clearly true, but they seem to avoid directly claiming that low consumption increases the risk of child abnormalities.”
Spiegelhalter also pointed out that the Chief Medical Officers in the UK recently updated their own guidelines (pdf; see paragraphs 88 – 108) for drinking while pregnant or planning to conceive. These guidelines state that the “safest approach is not to drink alcohol at all, to keep risks to your baby to a minimum.” However, they point out that “definitive evidence particularly on the effects of low level consumption, remains elusive.”
“My feeling is that CDC’s guidance, in spite of their extremely careful wording, will be generally interpreted as a claim that any drinking at all increases the risk of abnormalities. The UK group considered this would be over-stating the evidence, and I agree,” Spiegelhalter says.
When asked for comment, the CDC said in an email: “The goal of the publication and our recommendations is to offer women and their partners the necessary facts to make informed decisions based on their personal circumstances…There is no known safe amount, no safe time, and no safe type of alcohol to drink during pregnancy.”