Emily Oster on the conventional wisdom of pregnancy.

Nov 4, 2013

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Darwin of DarwinCatholic recently pointed me, via Facebook, to an interview with author Emily Oster hosted by EconTalk host Russ Roberts.

Oster is the author of Expecting Better: Why the Conventional Pregnancy Wisdom is Wrong–And What You Really Need To Know.

I have been meaning to pick it up for some time; now, thanks to the instant-gratification feature on Amazon (aka the Kindle store) I should be reading some of this book later today if I get a chance.

Here are a few interview quotes gleaned from the transcript highlights posted on the EconTalk page.

OSTER: I think that patients sometimes will just say: "Look, I just want you to tell me what to do. I don't want to have to make this choice"….in combination with doctors sometimes saying: "Look, I don't have 45 minutes to go through all this with you; I'm just telling you, you should make this choice."

I think those two things….interact poorly in a way that makes us not always make the best choices.

[Y]esterday I was on the radio with a doctor who said: "Well, statistics is really hard, and so …we shouldn't really expect people to be making a lot of these decisions with data."

And I think … "Are you kidding? You *have* to make these decisions with data."

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OSTER: I think one of the things that is definitely true is there is variation across doctors. And there is also this very clear set of constraints that I think doctors face, some of which just has to do with not having that much time and some of which has to do with legal issues.

…And I think for both of those reasons, it is in some sense incumbent on women to think through these choices for themselves.

And this extends past pregnancy into other parts of medicine: that there just isn't really a choice–you have to do this, to some extent, by yourself. There isn't another option.

On one of her examples, caffeine use during pregnancy:

OSTER: [I]n a lot of what I researched in pregnancy there is a very clear problem with causality….

So, the concern with having too much caffeine in pregnancy is that you might have a miscarriage. …. And so the way that this is studied early in pregnancy is you look at women who drank some coffee early in pregnancy; you ask them how much coffee they had; and you look at their rate of miscarriage and you compare them to women who didn't have coffee, and you look across different amounts of coffee.

[W]hat you find is…

that up to 200 mg, which is about 2 eight-ounce cups, is fine….you really don't see any increased risk of miscarriage up to that level.

When you start looking at, like, 8 cups of coffee, you see ….that there is an increased risk of miscarriage.

When you look in the middle, like 3, 4 cups a day, the evidence is a little bit mixed.

So … it's clear a little bit is okay; it's probably the case that a lot is a problem; but in this intermediate stage it's unclear.

And part of the issue is that when you look at these studies, the kind of women who drink coffee are just different from the kind of women who don't. And this is a problem in any observational study like this. And they are different in ways that are also, themselves, linked to miscarriage.

[W]omen who drink coffee tend to be older. Age is the biggest issue with this.

In addition, in the case of coffee–and this was in some sense the most interesting thing for me research-wise–there is also a problem with nausea. So, if you are nauseous in early pregnancy it's a very good sign about the health of the pregnancy. Women who are nauseous–good news, ladies: you are less likely to miscarry. But women who are nauseous are also more likely to avoid coffee.

So when you look at women and you see some of them drink a lot of coffee, those women are also on average women who are less nauseous. And when you see that they then miscarry at higher rates, it may well be just that not being nauseous is a sign of miscarriage and caused them to drink coffee, but it's not that the coffee caused the miscarriage. And I think getting around that kind of challenge is very complicated.

There's more, on epidurals, alcohol, deli meat, and cats, among other things. Unfortunately the interview transcript is poorly formatted, but you can also listen if that's your thing.

Comments

6 responses to “Emily Oster on the conventional wisdom of pregnancy.”

mandamum

November 4, 2013

I saw an article about her book in my local paper, and was glad someone is looking at the research and speaking about it on a popular level. One quote they had from her was something to the effect that if the local OB actually followed, or at least mentioned, the recommendations from ACOG, many of these issues would already be addressed. This was in response to a jab about her statements going against ACOG recs (which apparently many of them don’t).
I have heard that OB is the type of medicine least likely to be affected by what the research says…. here’s hoping that can change.
(I read another article recently about “group” appts for expectant mothers at a similar point in pregnancy, so these longer discussions can be had without causing problems to the practice. The personal stuff – labs, exams – is handled in private appts, but the “do you have any concerns” stuff is done together. Mmm…I like my midwifery practice.)

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Jenny

November 4, 2013

I haven’t listened to the podcast yet, but I find the coffee correlation/causation problem fascinating.
I usually have one good week after a positive pregnancy test before I get knocked on my rear. But even in that good week, my tolerance for coffee disappears. It doesn’t make me nauseous, but it is like my body can no longer process it. After drinking as little as a quarter cup, my heart is pounding and my hands are shaking. You would think I had taken espresso shots. I stop drinking it for most of the pregnancy and can only tolerate small amounts in the third trimester.
So is my body protecting the baby from the caffeine? Or is it just another reaction to indicate my hormones are pumping?

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Jenny

November 4, 2013

I’ve listened to the interview now. The insanity around pregnancy has to have some pushback. I remember my cousin, who consumes copious amounts of coffee, being so happy because her doctor was “allowing” her to have one cup a day while pregnant. That was after she struggled with total abstinence and had to go and beg a reprieve.
One of the big “requirements” when I was pregnant with my oldest was to sleep only on the left side. Does she say anything about that particular panic? It seems to have receded.
Something that caught my attention in the interview is that it seems she found evidence supporting behavior she likes and not for behavior she doesn’t like, i.e cigarettes. In the section on alcohol she teases out the data to find a spot between total abstinence and binge drinking. Of course binging is bad, what about one drink? Cigarettes didn’t seem to get the same treatment. Cigarettes bad. I would be curious to know if she addresses the continuum of smoking. Of course a pack a day is bad, what about one cigarette on Sunday afternoon?
Full disclosure: I don’t smoke and never have, but the topics seemed to get unequal treatment.

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mandamum

November 4, 2013

I think the coffee thing is a funny one – for me it varies by the day, but I like a warm drink in the morning, and most mornings until very recently (almost 3rd Trimester) I could enjoy very milky cafe au lait, but my usual black tea with milk left me nauseous and sloshy feeling the rest of the day. In other pregnancies, I’ve been off all but just hot vanilla milk in the mornings until after the first trimester, but then usually I can just go back to my tea.

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MrsDarwin

November 5, 2013

What does she find about going off salt for edema? My ankles and feet are items of wonder right now, if not of beauty.

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Caroline M.

November 26, 2013

That was probably because smoking is bad for you in general. Drinking red wine can be very healthy as long as you’re not an alcoholic, but there are no health benefits to smoking – quite the reverse. So whether you’re pregnant or not, the research does show that smoking leads to lung cancer. And lung cancer ain’t pretty….

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