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| Book cover for "Expecting Better." |
I recently announced the birth of my little baby girl. When I was pregnant this time, I read the book Expecting Better: Why the Conventional Pregnancy Wisdom Is Wrong--and What You Really Need to Know [affiliate link] by Emily Oster. (I have the 2021 edition.) I like this book and I recommend it, but with a few caveats.
Overall, I like the way Oster thinks. She is a math person like me, and when she got pregnant and was informed about all the "rules" that pregnant people are supposed to follow, she noticed that many of them didn't really make sense. And when she had to make decisions during the pregnancy, and asked for the data that one would clearly need to make those decisions, that data wasn't readily available. Instead, doctors were only able to give her one-size-fits-all advice. She wanted to look at the risks and benefits herself and make a decision based on her own individual situation- this is obviously what people should do, right? So why wasn't that data available?
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The pregnancy rules
Let's talk about the pregnancy "rules." Wow, when you get pregnant, there are so many things you're not allowed to eat. You're not allowed to have sushi, or deli meats, or precut fruit, or alcohol, or fish that are high in mercury, or rare steak, and so on and so on. SO MANY RULES. During my first pregnancy, I read the book "What to Expect When You're Expecting," and basically the whole book is like, "Is it okay to do xyz during pregnancy? Well, studies show there could be a slight risk, so, better not. Oh, but what if you already did it? Well don't worry, it's probably fine!" and I just felt like that didn't really make sense.
Oster also feels like these "rules" don't make sense. For example, many of these foods are off-limits because of the risk of food poisoning (sushi, rare steak, deli meat, precut fruit, etc). But, Oster asks, if I was eating sushi all the time before I got pregnant, and never got food poisoning, why is it suddenly a problem now? And, shouldn't everyone avoid bad sushi that gives you food poisoning, not just pregnant people? And, if I do get food poisoning, well obviously that's bad, nobody has a fun time with food poisoning, but is it actually any worse when I'm pregnant than when I'm not?
This is great! These are the questions that we absolutely should be asking! But instead, these "rules" are presented to pregnant people like they are ironclad rules, like if you eat precut fruit, it's BAD for your baby, OH NO!!! I've seen the amount of stress and anxiety this puts on pregnant people- because, it's seen as, yeah it's tough to give these things up during pregnancy, but it's for YOUR BABY, and you'd DO ANYTHING for YOUR BABY, right? Emotionally making it very high-stakes, when actually the reality is that these things are normally not a problem at all- the only problem would be if you happen to eat one that's contaminated with bacteria that causes food poisoning, and also if it happens to be a type of bacteria that is particularly harmful to the unborn baby (like listeria), and also if it ends up being serious enough to harm the baby.
I've seen women on pregnancy forums in a panic like "I ate sushi yesterday, I didn't know I wasn't supposed to!" and other women are telling them "don't worry, it's fine." I even saw one post that said "I really really want a sub from Jimmy John's but I know I can't eat cold cut meats during pregnancy" and people were replying to tell her it's fine to eat it, and she replied, "no, I had a miscarriage before, so this time I'm going to do everything I can to keep this baby safe" ... and I just... this makes me sad, because miscarriage isn't related to following these rules. (I suppose maybe in some of those rare cases where you eat the "bad" food and, unluckily, you do get food poisoning, there might be a risk of miscarriage.) And women are putting so much stress on themselves trying to be perfect, taking these rules super-seriously, when the actual data doesn't support that at all.
In my first pregnancy, I completely gave up on following the "rules", somewhere around 12 weeks. Because I could see that I was going to have depression. I had such bad nausea all the time, all food was repulsive, and when I finally thought of something I wanted to eat, guess what, it's something that I'm "not allowed" to eat. It was so bad. But up until 12 weeks, I had the mindset "I have to do this for my baby" until I couldn't anymore; I had to give up on following any of those "rules", because it was going to give me depression. It's like every damn day I had to dig myself out of the hole of figuring out what I can bear to eat, every day, 3 times a day, and actually more often than that because I need to eat snacks frequently or else I'll throw up. It often felt easier to just throw up instead, rather than try to figure out what food I can eat that's not completely repulsive to me.
Anyway. In the book, Oster looks at actual data about which kinds of food poisoning are actually more harmful during pregnancy, and which kinds of foods were involved in recent outbreaks of food poisoning. (Note that her data on that is from the US, so if you are in a different country, you may have different food safety risks. I'm in China, but I already ignore all these rules, so whatever.) She narrows it down to just a few foods that are worth avoiding, and advises readers to just ignore the rules about the others. (And then there's another section about evaluating the rules about fish that are high in mercury- this is a separate issue from the food poisoning.)
Yes, that whole section is great. (And in my first pregnancy, maybe if I had had a more realistic view of which rules actually mattered, and how to keep them in perspective, maybe I wouldn't have had to just completely give up on all of the rules.)
Another thing the book talks about is drinking alcohol during pregnancy. Personally, I don't drink alcohol at all because I don't like the taste, so this is not an issue for me, but apparently a lot of people really hate the fact that they're not allowed to drink alcohol during pregnancy. And this is a "pregnancy rule" that's much more serious than the ones about sushi or whatever. Everybody knows pregnant people aren't allowed to drink alcohol. I've heard all kinds of warnings from "What to Expect When You're Expecting" and other pregnancy resources that "there is NO amount of alcohol that's been shown to be safe during pregnancy."
But, Oster found that it's common in European countries for people to have a glass of wine with dinner, even during pregnancy. And, her doctor told her it's okay to drink a little, just don't overdo it. So, which is it? If any amount of alcohol really is harmful to the baby, then her doctor shouldn't be saying that. But if it is okay to drink a little bit, then this shouldn't be treated as such an ABSOLUTE RULE. (Oster says it's like women aren't trusted to make good decisions, so all we get is these simplistic absolute rules instead.)
She looked at a bunch of scientific studies about alcohol and pregnancy. (The difficult thing, though, is it's not ethical to randomly assign pregnant people to drink alcohol- so pretty much the only studies you can find are about asking people after the fact "did you drink alcohol during pregnancy?" and there could be all kinds of other characteristics that that subgroup of people might also have, which would affect the results. For example, she found one study where many of the people who drank alcohol also used cocaine, and their babies had worse outcomes. Well, maybe don't do cocaine during pregnancy.) Her conclusion, after presenting several studies, was that it is okay to have a small amount of alcohol during pregnancy (and she gave specific guidelines about the amounts- which turned out to be different depending on which trimester you're in). This is apparently a reason why there is controversy surrounding this book- because Oster says that it's NOT true that you have to totally avoid alcohol during pregnancy. Like I said, I don't drink at all, so it doesn't matter to me, but apparently there are people who strongly criticize this book for this reason.
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My concerns about some of her conclusions
I like her intuition in this book. But, I have some hesitation about accepting all of her conclusions. Her background is in economics, not medicine, so there may be some key pieces of information on health/pregnancy that she is missing, which might lead her to draw conclusions that are incorrect. What I mean is, if your doctor tells you "xyz is a bad idea during pregnancy" and then you go read a scientific paper that shows the reality is more complicated than that, and you draw the conclusion that "xyz is NOT bad"- well, what if there's something you missed? What if there's some other piece of information which is obvious to your doctor, but you didn't know about, which causes you to misinterpret the academic paper you read?
She should definitely run her conclusions by a doctor, before publishing them in her book. And, to some extent she did- her "Acknowledgements" section says that the book had a medical editor (Emily L. Seet) who is a doctor, and the "Foreword" of the book is written by a doctor (Nathan Fox) who says her conclusions are right. So... okay that's good, but it doesn't really give me confidence that every single thing was thoroughly fact-checked by someone with actual experience in the field of healthcare/pregnancy. It's not clear to me whether these doctors really checked and agreed with everything the book said.
I like her intuition, and she gives reasons to support her conclusions which seem to make a lot of sense, but since her training is not in this field, how do I know whether there's something she's missing?
I have a few examples:
There's a section in the book about the claim that "women's fertility declines after age 35." Typically in mainstream culture, the way people understand this is, you HAVE TO have kids before you're 35, otherwise you won't be able to! But Oster felt that this couldn't possibly be right- it can't possibly be the case that there's such an abrupt cutoff. When she asked her doctor about if she should be concerned about her fertility decreasing, her doctor totally dismissed it- "don't worry, you're not 35 yet!" As if it's like, a magical cutoff. Oster didn't buy that, and went looking for better data on it. And yeah, women SHOULD have access to better data on this! You want to plan your life, but there's this idea floating around that you need to have a baby before age 35 even if it doesn't really fit your life plan, because otherwise you'll NEVER be able to have a baby. Since that can be such a huge factor in long-term decision-making, we absolutely SHOULD have better data on it.
So, Oster went looking for better data. She found a study from the 1800s, that showed women's age of marriage and age when their first child was born. Based on this, she could calculate stats like: if you got married (and presumably started having unprotected sex) at age 20-25, what's the probability you have a baby, and so on for other age ranges. Her conclusion is that fertility does decline with age, but there's not a hard cutoff at age 35, and if you start trying to have a baby after age 35, odds are you WILL be able to have a baby.
So, yes, sure, this makes sense, intuitively. This is certainly a better answer than the common rhetoric that implies 35 is a magical cutoff for women's fertility. But- the study was from the 1800s. There could be SO MANY WAYS that people's fertility now is different than back then. We can't just accept the numbers from Oster's calculations and assume they're true for us now. Yes, they're certainly more accurate than fearmongering about "you have to have a baby before age 35 or you'll lose your chance forever!" but that doesn't mean they're necessarily correct.
So this is what I mean about some things in the book making sense intuitively, but I have concerns about whether the conclusions are correct- it is quite possible that there are other important factors she doesn't know about.
Another example: If you're trying to get pregnant, the "two-week wait" is a time of great anxiety. This is the 2-week span of time between when you have sex and when it's possible to detect a pregnancy with a pregnancy test (or, the time between when you have sex and when you get your period/ when you *miss* your period). During this time, you might be pregnant! Or you might not! Who knows! So here's a question: During the "two-week wait," should you follow the pregnancy rules? (For example, don't drink alcohol, just in case you're pregnant but don't know it yet.)
This is a very good question! (And, for a different twist: If you just found out you were pregnant, but you did things that pregnant people aren't supposed to do, before you even missed a period- is that bad for the baby?)
Oster answers it this way: During the two-week wait, if the egg has been fertilized and you are going to be pregnant, the embryo is still in the phase where all of its cells are identical. It's simply dividing the cells; it's not actually growing different body parts yet. So, she reasons, if breaking the "pregnancy rules" harms the embryo by causing some cells to die, well, either few enough cells die that it doesn't make a difference (and the remaining cells are identical to the ones that died, so it's not like your baby lost something), or enough cells die that the whole embryo dies and you never end up getting a positive pregnancy test anyway.
So, basically, probably don't need to worry about following the pregnancy rules during the two-week wait.
Throughout this whole line of reasoning, there were no studies cited or anything. I was SHOCKED at that. Oster just starts with the fact that all the cells in the embryo are identical at that stage of development, and reasons from there. And, yeah sure, maybe she's right. Her reasoning more or less makes sense. But there could be all sorts of other factors that play into this. I am not a doctor so I don't know- and Oster is not a doctor either. (For example, the idea that breaking the pregnancy rules will simply kill or not kill some number of cells- is that really how it works, or could there be more complicated effects than that? What about something affecting the pregnant person's body, which would then end up affecting the baby later, when it's no longer in the embryo stage? Also, I've heard that it's important to start taking prenatal vitamins before you even know you're pregnant, because that DOES affect some early development stuff!)
Like, yes, it absolutely makes sense to ask the question "does it matter if I follow the pregnancy rules during the time period when it's too early to know if I'm pregnant or not?" It's very logical to be concerned about that. (Also I love this part: "One friend admitted to compensating by getting drunk the day her period arrived every month.") But Oster's answer to this is, I would say, not based on reliable information. It's just speculation. It's the sort of thing that I might float as an idea in a blog post (hoping that maybe some commenters are more knowledgeable than me and can correct where I'm wrong), not the sort of thing I'd be confident enough to publish in a book.
Really what you need here is a scientific study of people who were having unprotected hetero sex and then some of them *did* follow the pregnancy rules during the two-week wait and some did *not*, and then you compare their results. (Did they get a positive pregnancy test or not, were there any problems during the pregnancy, etc.) But there's nothing like that at all in that section of the book.
One more example: Women in the later stages of pregnancy, who are told they have "low amniotic fluid" and it's suddenly a huge emergency and the doctor says they MUST induce labor right away, or else the baby is in DANGER! Yeah, this is totally a thing. Doctors telling you that you have "low amniotic fluid" and there's no time for you to ask questions and gather information about what's going on and what the risks are, so you can make an informed decision- no, you're in a panic because your baby [supposedly] might DIE if it's not born immediately, and you just do whatever the doctor tells you.
Oster says that studies show that low amniotic fluid is not as big of an emergency as it's made out to be. Yes, it can cause problems for the unborn baby, but usually there would be other indications of those dangers- if the only "problem" is low amniotic fluid, that's not necessarily a problem just by itself. Also, she found that amniotic fluid measurements were influenced by how much water the pregnant person drank before doing the ultrasound to measure.
So, her advice is to drink a lot of water before your ultrasound, so it will be less likely that they find you have "low amniotic fluid" and create a big panic about it.
Ummmmm. So my feeling on this is: Yes, she is correctly observing that something is off about the way doctors typically handle this. The data shows that inducing labor early because of "low amniotic fluid" doesn't really result in better outcomes than not doing that. And the measurement is affected by how much water you drink, but they don't tell you you're supposed to drink some standard amount- and then if you have a low measurement just because you happened to not drink water beforehand, they act like it's a BIG EMERGENCY. Something is off here.
BUT I'm not sure that the solution is to game the measurement by drinking a lot of water beforehand. They are measuring something that actually matters. But this advice treats it like the actual amount of amniotic fluid you have is fine whatever it is, and the important thing is just to get a measurement number high enough that your doctor doesn't start telling you wild stories about how your baby could die if they don't induce labor immediately.
(To be fair, there are some disclaimers in the book about how the level of amniotic fluid does matter, and could actually be a problem sometimes. But I'm not sure how to reconcile that with her overall approach in that section.)
My point is, overall I think Oster's intuition is very good when she points out things that don't make sense about pregnancy advice or the way doctors treat pregnant patients. Yes, she does correctly identify many illogical things, and pregnant people deserve to have better information about these things. But when Oster offers her own answers to those questions that she raises, I'm not sure her answers are right either. Since she's not a doctor, it's quite likely that she's missing some key insights, and possibly coming to wrong conclusions.
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Places where the book is spot-on
Even though there were a bunch of places where I felt her conclusions weren't reliable, there were also a lot of places where her conclusions and insights were spot-on.
For example, the section about prenatal testing. During pregnancy, there are tests they can do to screen for Down Syndrome and other genetic conditions. First, there's the "noninvasive prenatal screening" where blood is taken from the pregnant person and tested (because some of the unborn baby's chromosomes are floating around in the pregnant person's blood).
If the test comes back positive, there's a chance that it's a false positive, and there are other procedures that doctors can do to get a more accurate result: CVS (chorionic villus sampling) or amniocentesis. Both of these involve a big needle going into the uterus, so, uh, that's scary, and there's a risk that it could cause a miscarriage.
Oster wanted to know the exact probabilities that we're dealing with: Based on the pregnant person's age, what is the probability that the baby will have a genetic disorder? What is the rate of false positives or false negatives for these different tests? What is the probability of miscarriage for CVS/amniocentesis?
Yeah, very much makes sense that pregnant people would want to have that data, to make a decision about what tests to do!
Basically, the recommendation from the doctor was this: It's standard that everyone does the "noninvasive" blood test, and if that comes back negative, then you don't worry about it. If it's positive, then you do the CVS or amniocentesis. Also, the risk that CVS/amniocentesis would lead to a miscarriage is [supposedly] 1 in 200, so if the probability that your baby has a genetic disorder is greater than 1 in 200, it's recommended to do the CVS/amniocentesis test.
Oster wanted more detailed numbers than that, but the doctor didn't have data for her. And also, it turns out that the "1 in 200 chance" of a miscarriage is based on data from the 1970s, and now medical technology has improved and the risk is much lower.
And also she says, the recommendation to do the invasive test if the chance of having a baby with a disorder is greater than the chance of miscarriage only makes sense if both outcomes (miscarriage, or having a baby with a genetic disorder) are equally bad. !!!! Yes, good point! She says, shouldn't people base their decision on their own personal opinion about which one is worse, and how many times worse?
Yes, spot-on.
Another section that I thought was spot-on was the "am I going to be pregnant forever?" section. In the third trimester, pregnant people start worrying about preterm labor- so, it would be good to know the week-by-week probabilities of going into labor too early- because you DON'T want that to happen. But then, around 38-40 weeks when the baby is full-term and it's the right time for the baby to be born, it can feel like it's too long to wait, and you're just so exhausted from being pregnant, and just ready to be DONE, and you feel like you're going to be pregnant FOREVER. Yes, relatable.
Oster found statistics about when people go into labor, and made a chart with probabilities along the lines of "If you are pregnant at the beginning of week N, what's the probability you will give birth before the start of week N+1?"
Yes! Love this! See these are the numbers that pregnant people really need to know, because wow it's such a pain being pregnant. Just want to be done.
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Zofran and "if she really felt like she needed it"
One more thing that I want to point out, because it stood out to me. There's a chapter in the book about first-trimester nausea, and examining what kinds of medicines are safe for treating it. (Zofran is one of the medicines discussed in the book.) I personally had SUCH BAD nausea throughout the whole first trimester, both times I was pregnant, omg it was so bad, just spent the entire day trying not to throw up, and/or throwing up. Oh it was so bad. But I never considered taking any medicine for it, because I thought pregnancy is supposed to be that way- it's the baby's way of FORCING me to constantly eat protein.
Here's the bit from page 95 of the book that I want to point out:
Dwyer, the friend with the terrible nausea, was told that she could take Zofran if she "really felt like she needed it." Maybe her doctor didn't intend for this to have a chilling effect, but it did: she came away thinking it was dangerous for her baby, but if she cared only about herself she could take it. Who would be comfortable taking anything at that point?
Oh my goodness, this is so real.
This is what pregnancy is like. All these things that you may or may not be allowed to do, because they may or may not be "safe" for the baby, and... for all you know, your baby's life may be at stake. It's easy to feel like you have to just accept any amount of burdensome rules- even though you would NEVER let people boss you around like that if you weren't pregnant, and you would NEVER accept that kind of suffering if you weren't pregnant- because it's FOR YOUR BABY, you need to do it FOR YOUR BABY. (And this burden and anxiety is even bigger for people who have struggled with infertility or have had miscarriages, and they want to do everything they possibly can to finally have a baby.)
In feminism we talk about "bodily autonomy" a lot. And I'm pro-choice, which is also about bodily autonomy. "Pro-choice" is typically viewed in an oversimplified way, like it means "you can have an abortion if you choose to" and nothing else beyond that. I personally see it as much more: to be truly pro-choice would mean creating a society where people have access to contraception if they want that, where people have access to prenatal health care and other resources for having a baby if they want that, and safe abortion if they want that. It has to be about having ALL of the choices available, not just abortion.
Pregnancy is complicated, ethically, because there is a conflict between the bodily autonomy of the pregnant person and the fetus/embryo/unborn baby. (That's why I'm pro-choice: because it's complicated, nobody else knows the situation well enough to make a decision on it, other than the pregnant person.) One key thing is that pregnant people should be given realistic information about the "pregnancy rules" and what the actual risks are, not just a list of "here are all the things you're not allowed to do now, because you're pregnant." Not just accepting that any amount of burdensome rules is justified because it's FOR YOUR BABY, and if you LOVE YOUR BABY you will sacrifice yourself to follow all the rules, and if you don't then you are SELFISH. (Like I said, I was teetering on the edge of having depression during my first pregnancy, because of this mindset.) I want to have a conversation about bodily autonomy- in a wanted pregnancy- that is more nuanced than that.
This anecdote from the book- about being told it's okay to take anti-nausea medicine if you "feel like you really need it"- I mean, yeah, it very much comes across as "this might be dangerous to your baby, but if you value your own comfort more than your baby's life, then you can take it." (Which, by the way, is NOT the real situation- Oster presents data that shows Zofran is safe during pregnancy. And maybe the doctor didn't mean it that way.) The emotions around pregnancy, and the judgment on being a "good mom"- it makes it that much more difficult to actually get the real data and make informed decisions.
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Conclusion
I like this book, and I recommend it- though I don't think you should accept all of Oster's conclusions. She is good at identifying places where mainstream pregnancy advice doesn't make sense, but in some parts of the book, I'm not sure that her conclusions are correct either.
Also, this book shouldn't be the only book you read during pregnancy. You also should read a more standard pregnancy resource like "What to Expect When You're Expecting" (or just the What to Expect website). "What to Expect" has information on how the baby is developing at every week of pregnancy, what symptoms you can expect to have, what kinds of tests your doctor would do at different points during the pregnancy, possible complications, etc. It gives an overview of the whole thing. "Expecting Better" doesn't do that- it only focuses on the points where Oster believes that conventional advice is bad, or that more data should be provided to pregnant people to help them make decisions.
(I also have criticisms of "What to Expect When You're Expecting" though, for the way it presents the pregnancy rules, and also it's so extremely heteronormative and cisnormative.)
Overall, I relate to a lot of what Oster says in this book. I'm a math person and she is too. And there are so many things that you are told during pregnancy that don't really make sense- I'm glad to see a book pointing this out! I recommend this book to pregnant people who want to read a bunch of statistics.
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Related:
Pregnancy and Depression
What Pregnancy Taught Me About Being Pro-Choice
I Had Pre-Eclampsia
