Pandemic Baby Developmental Delays

Emily Oster

9 min Read Emily Oster

The COVID-19 pandemic has had impacts on children that go far beyond the effects of disease. We are beginning to get a better understanding of the impacts on school-age children, especially around learning. Many of the readers of this newsletter, however, are parents to smaller children. And if you’re in this group, you might have heard some scary coverage about COVID and infant development. But are those concerns real? Or just fearmongering?

There are, to my mind, two key questions to be asked here. The first is a narrower one: Does having COVID-19 during pregnancy impact child neurodevelopment? The second is broader: Has the experience of the pandemic (stress, lockdowns, lack of social interaction, illness of adults, etc.) impacted this younger age group? For older kids, we know the answer to the second question is yes, based on the dramatic declines in academic test scores. In that case, the mechanism (disrupted schools) is clear. But it’s less obvious that we’d see that with younger children.

To dig into this, we’ll look at what the data says about these two questions in turn.

It is worth saying up front: many of the concerns voiced about kids and the pandemic relate to long-term impacts. By definition of where we are, we cannot speak in either direction to concerns about impacts on school performance, adolescent health, or long-term mortality. At this point, the outcomes we can look at are limited to what we can study in early childhood.

In utero effects

I want to start with this question because I think it is the most decision-relevant. If you are pregnant, it’s necessary to make a series of choices about how careful to be around COVID. If it poses a particular in utero threat, that would be part of the calculus.

There is a large academic literature on the impacts of in utero pathogen exposure on long-term health and other outcomes. For example, in utero exposure to the 1918 flu appears to have had a variety of short- and long-term effects. These earlier experiences naturally suggest the hypothesis that COVID-19 exposure could have negative impacts. However: it’s not obvious this would carry over, for a variety of reasons (for example, we have better resources now).

There are two key papers on this in utero question.

The first was published in JAMA Pediatrics in January 2022. This study focuses on 255 infants born between March and December 2020. The researchers used a tool called the Ages & Stages Questionnaire to evaluate child development (it was also used throughout the papers discussed here).

To answer the question of in utero impacts, the authors compare infants of mothers who had COVID while in utero with those who did not. They find no differences in development between the two groups.

The second paper, this one in JAMA Network Open, finds the opposite. The authors analyze 7,772 live births, of which 222 are births to women with confirmed COVID-19 during pregnancy. The authors find that the children of mothers who had COVID during pregnancy are more than twice as likely to have a neurodevelopmental delay diagnosis relative to those without. This is especially true for COVID in the third trimester.

On the face of it, these findings are at odds. A closer look makes clear what is going on. In the first paper, the authors match the analysis on gestational age — effectively, comparing full-term infants with full-term, and preterm with preterm.

In the second, this matching isn’t done. And in that second paper, the authors observe large differences in preterm birth for exposed and unexposed women. Moreover, when they limit to full-term pregnancies or adjust their analysis for time spent in the hospitals, their effects are much smaller and no longer significant.

Pulling this together, the data suggests (as we know from other analyses) that COVID-19 — especially among unvaccinated women — increases the risk of preterm birth. Preterm birth is associated with an increased risk of developmental delay diagnosis (both because these delays are more common and probably because doctors are paying more attention). For this reason, COVID infection in pregnancy may impact children. But it’s the prematurity, not the COVID per se, that seems to be the mechanism.

From a practical standpoint, the main advice here is to get vaccinated prior to or during pregnancy. What we know about the impacts of COVID-19 on pregnant women suggests that by far the most significant risks are to those who are unvaccinated. These risks are preterm birth and other pregnancy complications.

Overall impacts

A much broader question is whether the pandemic has impacted child development in general. There are a number of possible mechanisms for this impact. Parental stress, lack of socialization, limited exposure to child care, masked child care providers, and more. None of these mechanisms are as clear-cut as those for older children in school, but many of them are plausible.

Identifying the effects here is a challenge given the data we currently have. To be more specific, the main way we would be able to discover impacts of the pandemic overall is to compare children over time based on their birth timing. We could compare some child development metric at age 1 among children who were born in 2018 with those who were born in 2020.

In order to do this type of analysis well, you need to be confident that other than the pandemic, everything else is held constant — the way you recruit the kids, the way you evaluate development, etc. At the risk of belaboring the comparison, when we do this analysis of elementary school test scores, it works because the tests are run the same way in each year, on the same groups.

In the long run, I do think we may be able to run this type of analysis for child development. In the short run, though, the studies we have of it are very problematic.

For example: we can return to the first of the papers discussed above. While that paper showed no differences between kids whose mothers had COVID-19 during pregnancy and those who did not, the overall cohort scored considerably lower than earlier birth cohorts on gross motor skills, fine motor skills, and a subdomain of the test called “personal-social.” These effects are reasonably large.

However: in this study, the comparison group and the pandemic group were recruited in totally different ways. The pandemic group was part of a cohort study recruited to examine COVID in pregnant women. The historical cohort was from a sample of children recruited for a different study, in an earlier time period. This protocol is fine from the standpoint of comparing within the pandemic-period group, because they were all recruited in the same way. But the difference across groups in recruitment means it is extremely difficult to learn anything from the comparison.

The journal published a comment on the article that, while somewhat snarky, I felt captured my point accurately: Although the authors claim that their data suggest “the potential for a significant public health crisis,” I believe the data should not be taken as suggesting anything, owing to the methodological limitations noted here.

A second paper, which is still a preprint, used a sample of mothers and infants who have been recruited in the same way since 2011. The researchers compare cognitive testing for children in this cohort born during the pandemic with those born before. This is good because it gets around the issue of differential recruitment. The results in this study are especially scary — the authors estimate a 27-to-37-point reduction in IQ, which is almost unheard-of.

In fact, this magnitude of an effect is extremely implausible. Even those most concerned about child development during this period do not think that the pandemic caused a 30-point IQ drop. And when you dig into this paper, it becomes clear what is going on. Much of the testing requires young children to understand instructions and words. In the pandemic period, the testers were masked. Without weighing in on the possible issues of masks in general with children, I think it is fair to say we’d expect it to matter a lot in this case, with young kids and unfamiliar interviewers.

This sample seems like a good one with which to answer these questions in the longer term, when we have the ability to run the tests the same way. But for now, it is also meaningless.

Perhaps the best study I found on the subject, though it didn’t get much attention, was this one. In it, the researchers looked at neurodevelopment scores for 1,024 children ages 6 months to 36 months, collected from pediatric practice records. They used the same pediatric practices before and after the pandemic, and the samples were all collected in the same way (they are parent-reported responses to a standard questionnaire).

In this study, the authors find no overall differences pre- and post-pandemic; there are some small differences in various domains, but not in any consistent direction. I find this reassuring, and the paper, to me, serves as a model of how this work might be done going forward.

The bottom line here is that we simply do not have enough information to either fully dismiss the concern or to embrace it. The various papers that scared you on this are flawed, but there isn’t some large and highly reliable study that would end our concerns.

Concluding thoughts

In reviewing this, I came away with two conclusions.

The first is that there should be more high-quality research on these questions. For all that we know about the pandemic’s impacts on children, it’s depressing that there is so little compelling research.

The second is that the media coverage of many of these studies is extremely problematic. If I look at the three studies of the overall pandemic impacts, the two worse ones, with scarier conclusions, got much more coverage than the better, less-scary paper. There may be reasons for this, but I think one of them is that fear sells. Especially to parents.

A mother holds a toddler on her lap and, together, they point at images in a book.

Mar 04 2022

10 min read

More on the CDC Developmental Milestones

Your questions answered

Emily Oster
A sitting infant holding up pointer fingers on both hands points to something off-camera.

Feb 21 2022

8 min read

New Developmental Milestones from the CDC

What changed and why

Emily Oster
Three babies are seen doing tummy time

Nov 28 2023

4 min read

When Should I Consider Physical Therapy for My Baby?

Hi Emily! I am curious about how exact babies need to be in hitting milestones. Our pediatrician is intelligent, lovely, Read more

Emily Oster

Jan 04 2024

19 min read

Learning to Speak

Learning to Speak With Michael Frank

Emily Oster

Instagram

left right
Just eat your Cheerios and move on.

Just eat your Cheerios and move on. ...

The AAP’s guidelines recommend sleeping in the same room as your baby “ideally for the first six months.” However, the risk of SIDS is dramatically lower after four months, and the evidence in favor of the protective effect of room sharing is quite weak (both overall and even more so after four months). There is also growing evidence that infants who sleep in their own room by four months sleep better at four months, better at nine months, and even better at 30 months.

With this in mind, it’s worth asking why this recommendation continues at all — or at least why the AAP doesn’t push it back to four months. They say decreased arousals from sleep are linked to SIDS, which could mean that babies sleeping in their own room is risky. But this link is extremely indirect, and they do not show direct evidence to support it.

According to the data we have, parents should sleep in the same room as a baby for as long as it works for them! Sharing a room with a child may have negative impacts on both child and adult sleep. We should give families more help in navigating these trade-offs and making the decisions that work best for them.

#emilyoster #parentdata #roomsharing #sids #parentingguide

The AAP’s guidelines recommend sleeping in the same room as your baby “ideally for the first six months.” However, the risk of SIDS is dramatically lower after four months, and the evidence in favor of the protective effect of room sharing is quite weak (both overall and even more so after four months). There is also growing evidence that infants who sleep in their own room by four months sleep better at four months, better at nine months, and even better at 30 months.

With this in mind, it’s worth asking why this recommendation continues at all — or at least why the AAP doesn’t push it back to four months. They say decreased arousals from sleep are linked to SIDS, which could mean that babies sleeping in their own room is risky. But this link is extremely indirect, and they do not show direct evidence to support it.

According to the data we have, parents should sleep in the same room as a baby for as long as it works for them! Sharing a room with a child may have negative impacts on both child and adult sleep. We should give families more help in navigating these trade-offs and making the decisions that work best for them.

#emilyoster #parentdata #roomsharing #sids #parentingguide
...

It was an absolute pleasure to be featured on the @tamronhallshow! We talked about all things data-driven parenting and, in this clip, what I call the plague of secret parenting. To balance having a career and having a family, we can’t hide the fact that we’re parents. If mothers and fathers at the top can speak more openly about child-care obligations, it will help us all set a new precedent.

Watch the full segment at the link in my bio 🔗

#tamronhall #tamronhallshow #emilyoster #parentingsupport #workingparents

It was an absolute pleasure to be featured on the @tamronhallshow! We talked about all things data-driven parenting and, in this clip, what I call the plague of secret parenting. To balance having a career and having a family, we can’t hide the fact that we’re parents. If mothers and fathers at the top can speak more openly about child-care obligations, it will help us all set a new precedent.

Watch the full segment at the link in my bio 🔗

#tamronhall #tamronhallshow #emilyoster #parentingsupport #workingparents
...

Invisible labor. It’s the work — in our households especially — that has to happen but that no one sees. It’s making the doctor’s appointment, ensuring birthday cards are purchased, remembering the milk.

My guest on this episode, @everodsky, has come up with a solution here, or at least a way for us to recognize the problem and make our own solutions. I’ve wanted to speak with Eve for ages, since I read her book Fair Play. We had a great conversation about the division of household labor, one I think you’ll get a lot out of!

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

#emilyoster #parentdata #parentdatapodcast #parentingpodcast #householdtips #fairplay #invisiblelabor

Invisible labor. It’s the work — in our households especially — that has to happen but that no one sees. It’s making the doctor’s appointment, ensuring birthday cards are purchased, remembering the milk.

My guest on this episode, @everodsky, has come up with a solution here, or at least a way for us to recognize the problem and make our own solutions. I’ve wanted to speak with Eve for ages, since I read her book Fair Play. We had a great conversation about the division of household labor, one I think you’ll get a lot out of!

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

#emilyoster #parentdata #parentdatapodcast #parentingpodcast #householdtips #fairplay #invisiblelabor
...

Prenatal vitamins 💊 If there is any product that seems designed to prey on our fears, it’s this one. You’re newly pregnant and you want to do it right. Everyone agrees you need prenatal vitamins, so you get them. But do you want to be that person who just… buys the generic prenatal vitamins?

Good news: fancier vitamins are not better.  Folic acid is the most important prenatal ingredient. Iron (with vitamin C) and DHA are also nice to have. Other included ingredients have only weak or no evidence to support their use. (If you do not consume animal products, add B12, plus a few others depending on your diet.)

Vitamins are just vitamins. Any prenatal vitamin that contains these is enough. 

Comment “Link” for a DM to an article with everything you need to know about prenatal vitamins.

#emilyoster #parentdata #prenatalvitamins #pregnancydiet #pregnancytips

Prenatal vitamins 💊 If there is any product that seems designed to prey on our fears, it’s this one. You’re newly pregnant and you want to do it right. Everyone agrees you need prenatal vitamins, so you get them. But do you want to be that person who just… buys the generic prenatal vitamins?

Good news: fancier vitamins are not better. Folic acid is the most important prenatal ingredient. Iron (with vitamin C) and DHA are also nice to have. Other included ingredients have only weak or no evidence to support their use. (If you do not consume animal products, add B12, plus a few others depending on your diet.)

Vitamins are just vitamins. Any prenatal vitamin that contains these is enough.

Comment “Link” for a DM to an article with everything you need to know about prenatal vitamins.

#emilyoster #parentdata #prenatalvitamins #pregnancydiet #pregnancytips
...

When it comes to introducing your newborn to the world, timing matters. It’s a good idea to minimize germ exposure in the first 6-8 weeks; after that, it’s inevitable and, very likely, a good idea! This doesn’t mean you need to be trapped inside. The most significant exposure risks are from seeing other people at home — family, etc. These interactions are not infinitely risky, but they do pose more risk than a walk or a trip to the grocery store, since they involve closer interaction. Think simple and make sure everyone is washing their hands before holding the baby. 💛

#parentdata #emilyoster #newborncare #parentingadvice #parentingtips

When it comes to introducing your newborn to the world, timing matters. It’s a good idea to minimize germ exposure in the first 6-8 weeks; after that, it’s inevitable and, very likely, a good idea! This doesn’t mean you need to be trapped inside. The most significant exposure risks are from seeing other people at home — family, etc. These interactions are not infinitely risky, but they do pose more risk than a walk or a trip to the grocery store, since they involve closer interaction. Think simple and make sure everyone is washing their hands before holding the baby. 💛

#parentdata #emilyoster #newborncare #parentingadvice #parentingtips
...

The first edition of Hot Flash is out now! Comment “Link” for a DM to learn more about the late-reproductive stage.

There are times when we expect hormonal shifts. Our reproductive lives are bookended by puberty and menopause. We discuss those changes often because they are definitive and dramatic — a first period is something many of us remember clearly. But between ages 13 and 53, our hormones are changing in more subtle ways. During the late-reproductive stage (in your 40s), you can expect a lot of changes in your menstrual cycle, including the length and symptoms you experience throughout. It’s an important time in our lives that is often overlooked!

🔥 Hot Flash from ParentData is a weekly newsletter on navigating your health and hormones in the post-reproductive years. Written by Dr. Gillian Goddard, Hot Flash provides all of the information you need to have a productive, evidence-based conversation about hormonal health with your doctor.

#emilyoster #parentdata #hotflash #perimenopause #womenshealth

The first edition of Hot Flash is out now! Comment “Link” for a DM to learn more about the late-reproductive stage.

There are times when we expect hormonal shifts. Our reproductive lives are bookended by puberty and menopause. We discuss those changes often because they are definitive and dramatic — a first period is something many of us remember clearly. But between ages 13 and 53, our hormones are changing in more subtle ways. During the late-reproductive stage (in your 40s), you can expect a lot of changes in your menstrual cycle, including the length and symptoms you experience throughout. It’s an important time in our lives that is often overlooked!

🔥 Hot Flash from ParentData is a weekly newsletter on navigating your health and hormones in the post-reproductive years. Written by Dr. Gillian Goddard, Hot Flash provides all of the information you need to have a productive, evidence-based conversation about hormonal health with your doctor.

#emilyoster #parentdata #hotflash #perimenopause #womenshealth
...

There are plenty of reels telling you how to parent. Plenty of panic headlines saying that “studies show” what’s best for your kid. Even good data, from a trusted source, can send us into a spiral of comparison. But I want you to remember that no one knows your kid better than you. It’s important to absorb the research, but only you will know the approach that works best for you and your child. 💙

Now tell me in the comments: what’s a parenting move you’ve made recently that feels right to you?

#parentingcommunity #parentingsupport #parentingquotes #emilyoster #parentdata

There are plenty of reels telling you how to parent. Plenty of panic headlines saying that “studies show” what’s best for your kid. Even good data, from a trusted source, can send us into a spiral of comparison. But I want you to remember that no one knows your kid better than you. It’s important to absorb the research, but only you will know the approach that works best for you and your child. 💙

Now tell me in the comments: what’s a parenting move you’ve made recently that feels right to you?

#parentingcommunity #parentingsupport #parentingquotes #emilyoster #parentdata
...

Let’s talk about sex (after) baby! Today on the podcast, I was lucky enough to speak with @enagoski about her new book on sexual connection in long-term relationships. Especially after having kids, this is something many people struggle with. Emily tells us to stop worrying about what’s “normal” and focus on pleasure in its many forms.

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

#parentdata #parentdatapodcast #emilyoster #emilynagoski #comeasyouare #cometogether #longtermrelationship #intimacy #relationships

Let’s talk about sex (after) baby! Today on the podcast, I was lucky enough to speak with @enagoski about her new book on sexual connection in long-term relationships. Especially after having kids, this is something many people struggle with. Emily tells us to stop worrying about what’s “normal” and focus on pleasure in its many forms.

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

#parentdata #parentdatapodcast #emilyoster #emilynagoski #comeasyouare #cometogether #longtermrelationship #intimacy #relationships
...

Ever wondered if you can safely use leftover baby formula? 🍼 The CDC says to throw out unused formula immediately because of the risk of bacterial growth. However, research suggests that bacterial concentrations do not appreciably increase after 3, 12, or even 24 hours at refrigerator temperatures. Good news! This means there’s not a strong data-based reason to throw out formula right away if you store it in the fridge.

Comment “Link” for a DM to an article on another common formula question: should you throw away old formula powder?

#emilyoster #parentdata #babyformula #babyfeeding #parentingstruggles

Ever wondered if you can safely use leftover baby formula? 🍼 The CDC says to throw out unused formula immediately because of the risk of bacterial growth. However, research suggests that bacterial concentrations do not appreciably increase after 3, 12, or even 24 hours at refrigerator temperatures. Good news! This means there’s not a strong data-based reason to throw out formula right away if you store it in the fridge.

Comment “Link” for a DM to an article on another common formula question: should you throw away old formula powder?

#emilyoster #parentdata #babyformula #babyfeeding #parentingstruggles
...

What’s the most important piece of advice for new parents? Here’s one answer, but I want to hear from you! Share your suggestions in the comments ⬇️

#emilyoster #parentdata #parentingtips #parentingadvice #newparents #parentingcommunity

What’s the most important piece of advice for new parents? Here’s one answer, but I want to hear from you! Share your suggestions in the comments ⬇️

#emilyoster #parentdata #parentingtips #parentingadvice #newparents #parentingcommunity
...

What's in the bag of a Vagina Economist? 👀 Someone please tell me this looks familiar to you.

What`s in the bag of a Vagina Economist? 👀 Someone please tell me this looks familiar to you. ...

Comment ”link” for a DM to learn more about tongue ties 🔗

Breastfeeding is often difficult, especially at the start. For babies with tongue ties, many infants (and their moms) struggle to get the hang of a good latch. This can lead to painful nipples and to inefficient feeding, and then low weight gain.

So what does the data say about the increasingly common practice of cutting tongue-ties in infants to improve breastfeeding success? Several weeks ago, @nytimes published a long and quite scary article on this topic.

After diving into the data, here is what I found. There is limited evidence that frenotomy procedures improve breastfeeding efficacy and the harms of the procedure are minimal. Many women do report that it alleviates pain and helps them with breastfeeding. However, it should not be a first-line treatment for breastfeeding problems.

#parentdata #emilyoster #tonguetie #tonguetiebabies #breastfeedingsupport

Comment ”link” for a DM to learn more about tongue ties 🔗

Breastfeeding is often difficult, especially at the start. For babies with tongue ties, many infants (and their moms) struggle to get the hang of a good latch. This can lead to painful nipples and to inefficient feeding, and then low weight gain.

So what does the data say about the increasingly common practice of cutting tongue-ties in infants to improve breastfeeding success? Several weeks ago, @nytimes published a long and quite scary article on this topic.

After diving into the data, here is what I found. There is limited evidence that frenotomy procedures improve breastfeeding efficacy and the harms of the procedure are minimal. Many women do report that it alleviates pain and helps them with breastfeeding. However, it should not be a first-line treatment for breastfeeding problems.

#parentdata #emilyoster #tonguetie #tonguetiebabies #breastfeedingsupport
...

Tag a friend who needs to hear this 💛 For many choices in parenting, there is no one right answer. We can use research and data to make informed decisions, but ultimately, it won’t tell you what to do. Only you can decide what will be best for your kids and your family.

I’m here to remind you to take a deep breath and trust yourself. I’ll be here to support you along the way. 

Thank you to everyone who submitted videos, including:
@sarah.consoli
@jess_lynn627
@nicolevandenwills
@thedrblair
@ncbenedict29
@haleycimini
@iamkellysnodgrass
@calesse_smith
@garnet__gordon
@jencoopgaiser87
@danigirl18c
@jamielundergreen
@carly_comber
@thecelebratingmama
@emilyannbynum
@eeliz413

#emilyoster #parentdata #parentingadvice #parentingsupport #parentingquotes

Tag a friend who needs to hear this 💛 For many choices in parenting, there is no one right answer. We can use research and data to make informed decisions, but ultimately, it won’t tell you what to do. Only you can decide what will be best for your kids and your family.

I’m here to remind you to take a deep breath and trust yourself. I’ll be here to support you along the way.

Thank you to everyone who submitted videos, including:
@sarah.consoli
@jess_lynn627
@nicolevandenwills
@thedrblair
@ncbenedict29
@haleycimini
@iamkellysnodgrass
@calesse_smith
@garnet__gordon
@jencoopgaiser87
@danigirl18c
@jamielundergreen
@carly_comber
@thecelebratingmama
@emilyannbynum
@eeliz413

#emilyoster #parentdata #parentingadvice #parentingsupport #parentingquotes
...