Thinking About Pregnancy Like an Economist

By Emily Oster
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Torsten Mangner/flickr

In the fall of 2009 my husband, Jesse, and I decided to have a baby. We were both economics professors at the University of Chicago. We'd been together since my junior year of college and married almost five years. Jesse was close to getting tenure, and my work was going pretty well. My 30th birthday was around the corner. We'd always talked about having a family, and the discussion got steadily more serious. One morning in October we took a long run together and, finally, decided we were ready. Or, at the very least, we probably were not going to get any more ready. It took a bit of time, but about eighteen months later our daughter Penelope arrived.

I'd always worried that being pregnant would affect my work--people tell all kinds of stories about "pregnancy brain," and missing weeks (or months) of work for morning sickness. As it happens, I was lucky and it didn't seem to make much difference (actually having the baby was another story). But what I didn't expect at all is how much I would put the tools of my job as an economist to use during my pregnancy.

This may seem odd. Despite the occasional use of "Dr." in front of my name, I am not, in fact, a real doctor, let alone an obstetrician. If you have a traditional view of economics, you're probably thinking of Ben Bernanke making Fed policy, or the guys creating financial derivatives at Goldman Sachs. You would not go to Alan Greenspan for pregnancy advice. But here is the thing: the tools of economics turn out to be enormously useful in evaluating the quality of information in any situation. Economists' core decision-making principles are applicable everywhere, including the womb. When I got pregnant, I learned pretty quickly that there is a lot of information out there about pregnancy, and a lot of recommendations. But neither the information nor the recommendations were all good. The information was of varying quality, and the recommendations were often contradictory and occasionally infuriating. In the end, in an effort to get to the good information--to really figure out the truth--and to make the right decisions, I tackled the problem as I would any other, with economics.

Ultimately, microeconomics is the science of making decisions--a way to structure your thinking so you make good choices. Making good decisions--in business, and in life--requires two things: the right data, and the right way to weigh the pluses and minuses of a decision personally. The key is that even with the same data, this second part--this weighing of the pluses and minuses--may result in different decisions for different people. Individuals may value the same thing differently. Making this decision correctly requires thinking hard about the alternative, and that's not going to be the same for everyone. This isn't just one way to make decisions. It is the correct way. So, naturally, when I did get pregnant I thought this was how pregnancy decision making would work, too. Take something like amniocentesis. I thought my doctor would start by outlining a framework for making this decision--pluses and minuses. She'd tell me the plus of this test is you can get a lot of information about the baby; the minus is that there is a risk of miscarriage. She'd give me the data I needed. She'd tell me how much extra information I'd get, and she'd tell me the exact risk of miscarriage. She'd then sit back, Jesse and I would discuss it, and we'd come to a decision that worked for us. This is not what it was like at all.

In reality, pregnancy medical care seemed to be one long list of rules. In fact, being pregnant was a lot like being a child again. There was always someone telling you what to do. It started right away. "You can have only two cups of coffee a day." I wondered why--what were the minuses? What did the numbers say about how risky this was? This wasn't discussed anywhere. Then we got to prenatal testing. "The guidelines say you should have an amniocentesis only if you are over thirty-five." Why is that? Well, those are the rules. Surely that differs for different people? Nope, apparently not (at least according to my doctor). Pregnancy seemed to be treated as a one-size-fits-all affair. The way I was used to making decisions--thinking about my personal preferences, combined with the data--was barely used at all. This was frustrating enough.

Making it worse, the recommendations I read in books or heard from friends often contradicted what I heard from my doctor. Pregnancy seemed to be a world of arbitrary rules. It was as if when we were shopping for houses, our realtor announced that people without kids do not like backyards, and therefore she would not be showing us any houses with backyards. Worse, it was as if when we told her that we actually do like backyards she said, "No, you don't, this is the rule." You'd fire your real estate agent on the spot if she did this. Yet this is how pregnancy often seemed to work. This wasn't universal, of course; there were occasional decisions to which I was supposed to contribute. But even these seemed cursory. When it came time to think about the epidural, I decided not to have one. This wasn't an especially common choice, and the doctor told me something like, "Okay, well, you'll probably get one anyway." I had the appearance of decision-making authority, but apparently not the reality.

I don't think this is limited to pregnancy--other interactions with the medical system often seem to be the same way. The recognition that patient preferences might differ, which might play an important role in deciding on treatment, is at least sometimes ignored. But, like most healthy young women, pregnancy was my first sustained interaction with the medical system. It was getting pretty frustrating. Adding to the stress of the rules was the fear of what might go wrong if I did not follow them. Of course, I had no way of knowing how nervous I should be. I wanted a doctor who was trained in decision making. In fact, this isn't really done much in medical schools. Appropriately, medical school tends to focus much more on the mechanics of being a doctor. You'll be glad for that, as I was, when someone actually has to get the baby out of you. But it doesn't leave much time for decision theory. It became clear quickly that I'd have to come up with my own framework--to structure the decisions on my own.

That didn't seem so hard, at least in principle. But when it came to actually doing it, I simply couldn't find an easy way to get the numbers--the data--to make these decisions. I thought my questions were fairly simple, but the numbers were not forthcoming. I asked my doctor about drinking. She said that one or two drinks a week was "probably fine." "Probably fine" is not a number. The books were the same way. They didn't always say the same thing, or agree with my doctor, but they tended to provide vague reassurances ("prenatal testing is very safe") or blanket bans ("no amount of alcohol has been proven safe"). Again, not numbers. I tried going a little closer to the source, reading the official recommendation from the American Congress of Obstetricians and Gynecologists. Interestingly, these recommendations were often different from what my doctor said--they seemed to be evolving faster with the current medical literature than actual practice was. But they still didn't provide numbers.

To get to the data, I had to get into the papers on which the recommendations were based. In some cases, this wasn't too hard. When it came time to think about whether or not to get an epidural, I was able to use data from randomized trials--the gold standard evidence in science--to figure out the risks and benefits. In other cases, it was a lot more complicated. And several times--with alcohol and coffee, certainly, but also things like weight gain--I came to disagree somewhat with the official recommendations. This is where another part of my training as an economist came in: I knew enough to read the data correctly. Pregnancy suffers from a lot of misinformation. One or two weak studies can rapidly become conventional wisdom. At some point I came across a well-cited study that indicated that light drinking in pregnancy--perhaps a drink a day--causes aggressive behavior in children. The study wasn't randomized; they just compared women who drank to women who did not. When I looked a little closer, I found that the woman who drank were also much, much more likely to use cocaine.

More than even the actual recommendations, I found having numbers at all provided some reassurance. And then my friends got pregnant. Pretty much all of them at the same time. They all had the same questions and frustrations I had. Their doctors, like mine, had a recommendation. Sometimes there was an official rule. But they wanted to make the decision that was right for them. There was a limit to the role I could play--no delivering babies, fortunately (for me and, especially, the babies). But I could provide people with information, give them a way to discuss concerns with their OBs on more equal footing, help them make decisions they were happy with. And as I talked to more and more women it became clear that the information I could give them was useful precisely because it didn't come with a specific recommendation. The key to good decision making is taking the information, the data, and combining it with your own estimates of pluses and minuses. In some cases, the existing rule is wrong. In others, it isn't a question of right or wrong but what is right for you and your pregnancy. I looked at the evidence on the epidural, combined it with my own plus and minus preferences, and decided not to have one. My friend Jane looked at the same evidence and decided to have one. In the end, I felt fine eating deli meats; my college roommate Tricia looked at the evidence and decided she would avoid them. All of these are good decisions.

Pregnancy and childbirth (and child rearing) are among the most important and meaningful experiences most of us will ever have; probably the most important. Yet we are often not given the opportunity to think critically about the decisions we make. Instead, we are expected to follow a largely arbitrary script without question. It's time to take control: pick up a cup of coffee or, if you like, a glass of wine.


This is excerpted from the introduction to Emily Oster's Expecting Better: Why the Conventional Pregnancy Wisdom Is Wrong--and What You Really Need to Know.

This article available online at:

http://www.theatlantic.com/health/archive/2013/08/thinking-about-pregnancy-like-an-economist/278874/