Emily Oster

4 min Read Emily Oster

Emily Oster

Forever Chemicals in Breast Milk

A new study raised alarm—but should you worry?

Emily Oster

4 min Read

Last week, The Guardian published an article with this headline: Study Finds Alarming Levels of ‘Forever Chemicals’ in US Mothers’ Breastmilk. Perhaps not surprisingly, breastfeeding people were…alarmed. Should they be?

Here’s the link to the original study. In this project, researchers collected breastmilk from 50 women and tested it for a class of chemicals know as PFAS (per- and polyfluoroalkyl substances). This is a group of chemicals which was historically commonly used in manufacturing. Due to concerns about their health and environmental impacts, some of these chemicals have been phased out of manufacturing over time, and levels in the bloodstream have dropped on average. However, some forms of these chemicals are still in use and their persistence means they are in our bloodstream.

The new study reports several findings. First, they find evidence of a number of chemicals in this class in breastmilk. This isn’t surprising; we know these are present in the bloodstream and we would expect transfer through milk. And, in fact, existing data has shown this.

The authors also show what I think are two pieces of “good” news (I mean, relatively good? But this my spin, not theirs). First, most of the evidence they put together shows the rates of these chemicals in milk going down over time. This is likely due to the phase out of their use in manufacturing. That’s a good sign! Second, they show that the implied exposure levels are lower than reference doses set by the EPA (these “reference doses” are levels of implied concern).

Stepping back, it is important to ask what the possible health risks are here? Existing data shows that higher levels of these chemicals are associated with cholesterol issues, asthma and possibly age of puberty. This review is helpful. Chemical levels do not seem to be associated with neurodevelopment outcomes (i.e. IQ or behavior problems) and several other health measures.

Although the study reported on by The Guardian mentions a link with cancer, that seems to show up in people who work in manufacturing with these compounds. The most consistent link for normal exposure in children is with the cholesterol-related measures. As with virtually everything in this space, it is difficult to be confident on causality here since exposure to these chemicals correlates with other confounding factors.

Bottom line: these type of chemical appear in breastmilk; they are appearing less over time due to phase out of the use of these; the levels are lower than EPA limits. On the flip side, existing work does make it seem like there are some possible health risks, if not enormous ones.

So…should you be alarmed?

I guess you can always be alarmed if you would like to be! But I’ll say two things. First, the bottom line findings here do not, to me, rise to level of alarming. I might go with “worth further study” or “notable”. But the paper didn’t find levels which outpaced what the EPA considers acceptable, they appear to be declining over time, and the consequences are a little vague.

Second: there isn’t really anything you can do about this. So, while it is fine to be alarmed, it’s not obviously useful. You could stop breastfeeding, but virtually no one is likely to suggest that’s the right solution, given how much everyone likes breastfeeding. There likely isn’t any short-term behavior you can undertake to lower your chemical levels. And even things like “advocate for less use of these chemicals in manufacturing” is less relevant here, since these are already being phased out to a large extent.

In the end, I think I’d personally put this in my favorite parenting-anxiety bucket. Maybe, just try not to think about it.

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We’re hiring an Associate Editor at ParentData! More details at my link in bio. Please share with the great writers and data-loving people in your network. 📊💻

We’re hiring an Associate Editor at ParentData! More details at my link in bio. Please share with the great writers and data-loving people in your network. 📊💻 ...

Do you brand things a certain way to get your kid to accept it? Like calling carrots “rabbit popsicles”? Or telling them to put on their “super speed socks” in the morning? Share your rebrands in the comments below! You never know who you might be helping out 👇

#emilyoster #funnytweets #relatabletweets #parentingjokes #kidssaythedarndestthings

Do you brand things a certain way to get your kid to accept it? Like calling carrots “rabbit popsicles”? Or telling them to put on their “super speed socks” in the morning? Share your rebrands in the comments below! You never know who you might be helping out 👇

#emilyoster #funnytweets #relatabletweets #parentingjokes #kidssaythedarndestthings
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Have you ever panic-googled a parenting question when everyone else is asleep? If so, you’re not alone. 

Today is the first episode of a new biweekly series on my podcast: Late-Night Panic Google. On these mini-episodes, you’ll hear from some familiar names about the questions keeping them up at night, and how data can help. First up: @claireholt!

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#parentdata #emilyoster #claireholt #parentingstruggles #parentingtips #latenightpanicgoogle

Have you ever panic-googled a parenting question when everyone else is asleep? If so, you’re not alone.

Today is the first episode of a new biweekly series on my podcast: Late-Night Panic Google. On these mini-episodes, you’ll hear from some familiar names about the questions keeping them up at night, and how data can help. First up: @claireholt!

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#parentdata #emilyoster #claireholt #parentingstruggles #parentingtips #latenightpanicgoogle
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Sun safety is a must for all ages, especially babies! Here are my tips for keeping your littlest ones protected in the sunshine:
☀️ Most importantly, limit their time out in hot weather. (They get hotter than you do!)
☀️ Keep them in the shade as much as possible when you’re out.
☀️ Long-sleeve but lightweight clothing is your friend, especially on the beach, where even in the shade you can get sunlight reflecting off different surfaces.
☀️ If you want to add a little sunscreen on their hands and feet? Go for it! But be mindful as baby skin tends to more prone to irritation.

Comment “Link” for a DM to an article on the data around sun and heat exposure for babies.

#sunsafety #babysunscreen #babyhealth #parentdata #emilyoster

Sun safety is a must for all ages, especially babies! Here are my tips for keeping your littlest ones protected in the sunshine:
☀️ Most importantly, limit their time out in hot weather. (They get hotter than you do!)
☀️ Keep them in the shade as much as possible when you’re out.
☀️ Long-sleeve but lightweight clothing is your friend, especially on the beach, where even in the shade you can get sunlight reflecting off different surfaces.
☀️ If you want to add a little sunscreen on their hands and feet? Go for it! But be mindful as baby skin tends to more prone to irritation.

Comment “Link” for a DM to an article on the data around sun and heat exposure for babies.

#sunsafety #babysunscreen #babyhealth #parentdata #emilyoster
...

I’m calling on you today to share your story. I know that many of you have experienced complications during pregnancy, birth, or postpartum. It’s not something we want to talk about, but it’s important that we do. Not just for awareness, but to help people going through it feel a little less alone.

That’s why I’m asking you to post a story, photo, or reel this week with #MyUnexpectedStory and tag me. I’ll re-share as many as I can to amplify. Let’s fill our feeds with these important stories and lift each other up. Our voices can create change. And your story matters. 💙

#theunexpected #emilyoster #pregnancycomplications #pregnancystory

I’m calling on you today to share your story. I know that many of you have experienced complications during pregnancy, birth, or postpartum. It’s not something we want to talk about, but it’s important that we do. Not just for awareness, but to help people going through it feel a little less alone.

That’s why I’m asking you to post a story, photo, or reel this week with #MyUnexpectedStory and tag me. I’ll re-share as many as I can to amplify. Let’s fill our feeds with these important stories and lift each other up. Our voices can create change. And your story matters. 💙

#theunexpected #emilyoster #pregnancycomplications #pregnancystory
...

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio!

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio! ...

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio!

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio! ...

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio!

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio! ...

Is side sleeping important during pregnancy? Comment “Link” for a DM to an article on whether sleep position affects pregnancy outcomes.

Being pregnant makes you tired, and as time goes by, it gets increasingly hard to get comfortable. You were probably instructed to sleep on your side and not your back, but it turns out that advice is not based on very good data.

We now have much better data on this, and the bulk of the evidence seems to reject the link between sleep position and stillbirth or other negative outcomes. So go ahead and get some sleep however you are most comfortable. 💤

Sources:
📖 #ExpectingBetter pp. 160-163
📈 Robert M. Silver et al., “Prospective Evaluation of Maternal Sleep Position Through 30 Weeks of Gestation and Adverse Pregnancy Outcomes,” Obstetrics and Gynecology 134, no. 4 (2019): 667–76. 

#emilyoster #pregnancy #pregnancytips #sleepingposition #pregnantlife

Is side sleeping important during pregnancy? Comment “Link” for a DM to an article on whether sleep position affects pregnancy outcomes.

Being pregnant makes you tired, and as time goes by, it gets increasingly hard to get comfortable. You were probably instructed to sleep on your side and not your back, but it turns out that advice is not based on very good data.

We now have much better data on this, and the bulk of the evidence seems to reject the link between sleep position and stillbirth or other negative outcomes. So go ahead and get some sleep however you are most comfortable. 💤

Sources:
📖 #ExpectingBetter pp. 160-163
📈 Robert M. Silver et al., “Prospective Evaluation of Maternal Sleep Position Through 30 Weeks of Gestation and Adverse Pregnancy Outcomes,” Obstetrics and Gynecology 134, no. 4 (2019): 667–76.

#emilyoster #pregnancy #pregnancytips #sleepingposition #pregnantlife
...

My new book, “The Unexpected: Navigating Pregnancy During and After Complications” is available for preorder at the link in my bio!

I co-wrote #TheUnexpected with my friend and maternal fetal medicine specialist, Dr. Nathan Fox. The unfortunate reality is that about half of pregnancies include complications such as preeclampsia, miscarriage, preterm birth, and postpartum depression. Because these are things not talked about enough, it can not only be an isolating experience, but it can also make treatment harder to access.

The book lays out the data on recurrence and delves into treatment options shown to lower risk for these conditions in subsequent pregnancies. It also guides you through how to have productive conversations and make shared decisions with your doctor. I hope none of you need this book, but if you do, it’ll be here for you 💛

#pregnancy #pregnancycomplications #pregnancyjourney #preeclampsiaawareness #postpartumjourney #emilyoster

My new book, “The Unexpected: Navigating Pregnancy During and After Complications” is available for preorder at the link in my bio!

I co-wrote #TheUnexpected with my friend and maternal fetal medicine specialist, Dr. Nathan Fox. The unfortunate reality is that about half of pregnancies include complications such as preeclampsia, miscarriage, preterm birth, and postpartum depression. Because these are things not talked about enough, it can not only be an isolating experience, but it can also make treatment harder to access.

The book lays out the data on recurrence and delves into treatment options shown to lower risk for these conditions in subsequent pregnancies. It also guides you through how to have productive conversations and make shared decisions with your doctor. I hope none of you need this book, but if you do, it’ll be here for you 💛

#pregnancy #pregnancycomplications #pregnancyjourney #preeclampsiaawareness #postpartumjourney #emilyoster
...

We are better writers than influencers, I promise. Thanks to our kids for filming our unboxing videos. People make this look way too easy. 

Only two weeks until our book “The Unexpected” is here! Preorder at the link in my bio. 💙

We are better writers than influencers, I promise. Thanks to our kids for filming our unboxing videos. People make this look way too easy.

Only two weeks until our book “The Unexpected” is here! Preorder at the link in my bio. 💙
...

Exciting news! We have new, high-quality data that says it’s safe to take Tylenol during pregnancy and there is no link between Tylenol exposure and neurodevelopmental issues in kids. Comment “Link” for a DM to an article exploring this groundbreaking study.

While doctors have long said Tylenol was safe, confusing studies, panic headlines, and even a lawsuit have continually stoked fears in parents. As a result, many pregnant women have chosen not to take it, even if it would help them.

This is why good data is so important! When we can trust the data, we can trust our choices. And this study shows there is no blame to be placed on pregnant women here. So if you have a migraine or fever, please take your Tylenol.

#tylenol #pregnancy #pregnancyhealth #pregnancytips #parentdata #emilyoster

Exciting news! We have new, high-quality data that says it’s safe to take Tylenol during pregnancy and there is no link between Tylenol exposure and neurodevelopmental issues in kids. Comment “Link” for a DM to an article exploring this groundbreaking study.

While doctors have long said Tylenol was safe, confusing studies, panic headlines, and even a lawsuit have continually stoked fears in parents. As a result, many pregnant women have chosen not to take it, even if it would help them.

This is why good data is so important! When we can trust the data, we can trust our choices. And this study shows there is no blame to be placed on pregnant women here. So if you have a migraine or fever, please take your Tylenol.

#tylenol #pregnancy #pregnancyhealth #pregnancytips #parentdata #emilyoster
...