Emily Oster on Pregnancy

Emily Oster (rising star economist) tackles the medical data on pregnancy.  Can you drink coffee and wine?  How much?  What about soft cheeses and deli meats?  Emily Oster is a top applied economist.  She is extremely skilled at reading and interpreting experimental data and applying cost benefit analysis.  That doesn't mean you have to agree with her preferred place on the risk spectrum or even her interpretation of the research, but it's an interesting endeavor none the less.

On bacteria risk:

Pregnant women are also given a long list of off-limit foods: deli meats, soft cheeses, sushi. These are restricted because of the risk of various pathogens. The most serious by far is listeria bacteria, to which pregnant women are especially susceptible; it can cause late miscarriage and stillbirth.

I knew I didn't want to snack directly on listeria bacteria, but I wondered how much I could limit my risk by avoiding certain foods. What share of listeria infections was due to soft cheeses, for instance? It turns out that queso fresco, a Mexican soft cheese, has been implicated in about 20% of listeria outbreaks since 1998, and deli turkey in 10%. The rest of the recent outbreaks seemed random. One involved cantaloupe, another one, celery.

I concluded that avoiding queso fresco and deli turkey was a good idea, but in the end I didn't feel that it made sense even to exclude other deli meats.

What about alcohol?

One big worry about drinking during pregnancy is that it will result in child behavior problems later. One of the best studies of this issue was published in 2010 in the British Journal of Obstetrics and Gynecology. What makes it a reliable study? The sample group was large (3,000 women), and the researchers collected information about maternal drinking during pregnancy—not afterward. The study also followed the children of these women through the age of 14 and looked at behavior problems starting at age 2.

The other thing I liked about this study was that it was run in Australia, where recommendations on drinking during pregnancy are more lax than in the U.S. Because the rules are more permissive, Australian women who drink occasionally aren't necessarily the kind of women who go against medical advice; it's more likely that differences in drinking levels there are just random variation. Drinkers in the study were classified in five groups: no alcohol, occasional drinking (up to one drink a week), light drinking (2-6 drinks a week) and moderate drinking (7-10 drinks a week).

The researchers compared the mothers' drinking level at 18 weeks of pregnancy with the children's behavior issues at age 2. They found that 11% of the children whose mothers did not drink during pregnancy had behavior problems—versus 9% of the children of light drinkers and 11% of the children of moderate drinkers. (Nearly 14% of 2-year-olds whose mothers occasionally drank had behavior problems, but the difference is small and, statistically, could have occurred by chance.) The results were very similar for older kids.

There's much more in the article.  And it looks like a book is coming too.