Last weekend, an article by economist Emily Oster called "Take Back Your Pregnancy" appeared in the Wall Street Journal. In this piece (as well as in her upcoming book, Expecting Better: How to Fight the Pregnancy Establishment with Facts), Oster makes some pretty bold—and in my view, completely irresponsible—claims about what's safe and what's not during pregnancy. For instance, she says, based on her analysis of existing data, that it's fine to drink way more caffeine than recommended throughout your pregnancy, and that light drinking throughout those 40-some weeks (including the first trimester) is just fine.
"When I looked at the data from hundreds of studies," she writes, "I found, basically, no credible evidence that low levels of drinking (a glass of wine or so a day) have any impact on your baby's cognitive development." And, in fact, in her book's "Bottom Line" guidelines on alcohol, she tells women that they "should be comfortable with" one to two drinks a week in the first trimester.
First off, it seems inappropriate to tell presumably grown women what they "should be" comfortable with—especially when the jury's still out, and we don't know what's really safe and what's not when it comes to alcohol and pregnancy. All we have are conflicting studies. But bigger than that is the problem of Oster's tendency to highlight studies that support her pot-stirring claims, and to bury or dismiss those that don't. Case in point: Oster claims she found "basically no credible evidence" that a few drinks would do any damage to baby's cognitive development, yet in her book, she includes a quick paragraph about a 2012 study of nearly 100,000 women that showed even light drinking (two or more drinks a week) was associated with an increased risk of miscarriage in the first trimester. Sure, miscarriage and cognitive development are two different things, but the blunt truth is that a fetus's cognitive development actually ends at the moment of miscarriage. I'd think that might be the more serious issue to take into consideration. In light of that, I really don't understand how she can, in good conscience, advise women to drink up to two drinks a week in those first crucial months, unless she's doing so simply to feel better about her own choices.
Moving onto caffeine in pregnancy, Oster once again seems to skew the data to suit her preferences (spoiler: this woman loves coffee). Even in the expanded chapter on caffeine in her book, Oster mentions only three human-based studies about on this subject: One that only involved 66 women, which makes the results inconclusive; another that showed no conclusive difference in miscarriage risk between women who drank caffeine and women who did not; and finally a study from 2008 (this one even employed a lot of technical controls to limit the chance of false results) that showed women who drink more than 200 mg of caffeine a day (about two small cups of coffee) have twice the risk of miscarriage. What I walk away with from all of that is that nobody really knows how much is safe, but there are signs that show that having more than 200 mg/daily could lead to fetal death. Not really something most moms want to risk, I'm sure, yet Oster continues with her "it worked for me" approach, advising readers in her "Bottom Line" on caffeine that "much of the evidence supports having three to four cups" daily.
There are definitely still questions about what's safe and what's not, but our stance on both caffeine and alcohol here at Parents is pretty simple: Why take the risk? We suggest that moms should limit their caffeine (of any kind!) to 200 mg a day, and that alcohol in any amount could put your pregnancy in danger.
At best, Oster's claims are incomplete, somewhat-biased journalism—and at worst, they are a flat-out danger to pregnant women and their families. I'm all for going to the source, reading up on studies, and advocating for your own health outcomes (not all doctors are up on the latest reports!), but you can't trust everything you read. And in this case, I'm hoping moms-to-be are taking Oster's advice with a massive grain of salt.