It's unfortunate that the link that made the front page here is to the BBC article rather than the NYTimes article [1] on the same study, as the NYTimes article much more clearly addresses a number of the points brought up by commenters here today. The NYTimes article briefly mentions other non-pregnancy related studies on the "pruning" of grey matter. One place to get a bunch of citations for studies on synaptic pruning is in the lit review of [2], since the NYTimes article itself doesn't have a citation for synaptic pruning research in adolescents. However, the NYTimes article does link to [3], an article about spontaneous theory of mind and synaptic density in 18-26 year olds. It looks at a this group of people not by age but by performance on theory of mind tasks, examining the relationship with structural MRI data from the participants. This sheds some light on efficiency and good performance on theory of mind tasks and the neuroanatomy of a person. I think for most HNers taking out thinking about pregnancy and looking at this study first would be useful in understanding the results -- we've all got a lot of preconceived notions about the effects of pregnancy that make it hard to think about the results of the study rationally.
Thanks for making this point, especially with regards to pregnancy being a loaded discussion topic.
In the original study I found it very interesting that the authors drew parallels between the "maturation" of a new mother's brain (grey matter reductions) and the brains of adolescents undergoing pregnancy. If this study replicates, I would love to see followup studies exploring measures of narcissism, time management, executive functioning and facial recognition over time in women shortly before, during and after pregnancy (and perhaps even two years afterwards). These are all areas in which adolescents experience significant variations in functioning when compared to the general population, and there could be a lot of fertile ground here.
One other thought that strikes me is how the grey matter alterations could potentially impact teenage mothers. If the mother's brain has not left adolescence by the time she experiences pregnancy, it would be interesting to see how the grey matter alterations differ, considering the authors' comparison.
Fertile ground... :) Moving on, agreed on follow-up studies. A study similar to this one looking at adolescent moms, non-moms, dads, and non-dads would be very interesting as well. After all, if a teen guy is undergoing similar pruning, what does that mean for his experience of a partner's pregnancy? Disentangling social factors from neuroanatomical changes in teen parents would be very hard, though, in societies where teen pregnancy is unusual and has big economic impacts. Might be easier to do someplace where it's more usual.
Anecdotally I can say it has a large effect on the male brain too. The lack of sleep and time changes you. You get ruthless against time stealers and start seeing 6 hours as a nice long sleep.
Full disclosure : I've had about 8hr sleep in 3 days,two sick kids...
People underestimate the effect of extreme sleep deprivation. For the first three months of my daughter's life, we didn't sleep for more than two hours at a time. The effect was profound - I was having auditory hallucinations, was paranoid, etc. It was only after she started sleeping through the night that I understood it was due to the lack of sleep.
I experienced this too with my daughter. She had colic so we got very little sleep for 3 months straight. I thought I was going crazy due to hallucinations and paranoia. All that went away when I was able to get at least 6 hours straight sleep per night.
Detected; I reject that it's relevant to the discussion, and I'm disappointed it's the top comment. Lifestyle changes aren't relevant to the research presented in the study. What would be relevant is contrary evidence of hormonal changes in males after their spouses undergo pregnancy, or structural alterations in the brain. Of course each parent is impacted by literally taking care of an infant, but what does that have to do with one gender experiencing grey matter reductions?
You know what's super-interesting? Although it's deeply under-researched and still subject to a lot of argument, there's mounting evidence that men going through a partner's pregnancy experience significant hormonal changes as well. Papers like [1] and [2] are really preliminary (small sample sizes, etc) and don't fully agree, but both show these hormonal changes in men going through pregnancy with a partner. How much is simply the stress of a life change? How much is couvade, or "sympathetic pregnancy"? How much is evolutionarily adaptive? No one knows yet, but it's an interesting piece to the puzzle: apparently the lower testosterone, higher cortisol, and changes in prolactin and estradiol that expectant fathers experience don't have the same neuroanatomical effects as the changes women experience in pregnancy.
That is irrelevant as it is consequence of life style change. Many mothers do not change lifestyle.
This however makes me think how much of the woman change is due to the life style change which is mandatory in given situation for majority of mothers and how much is programmed.
There are cultures where the grandparents or other relatives mostly take care of the children while the mother works (some parts of China), and there are people who pay for nannies to take care of the children at night.
Twin parent here...2 years and 2 months into it, and I would really like to know the limit of this "at least 2 years", because that original brain hasn't shown itself one bit, and I'd sure like to have it back.
I never thought a reduction could result in an improvement. The brain is so fascinating!
"The researchers found "substantial" reductions in the volume of grey matter in the brains of first-time mothers.
The grey matter changes occurred in areas of the brain involved in social interactions used for attributing thoughts and feelings to other people - known as "theory-of-mind" tasks.
The researchers thought this would give new mothers an advantage in various ways - help them recognise the needs of their child, be more aware of potential social threats and become more attached to their baby."
I'd be slightly careful here about separating out the findings from the speculation.
The study[1] looked at what changed in the women's brains, the regions in which it changed, and then tested to see which areas 'lit up' when viewing a picture of their own child vs. other children. In addition measurements were taken over time to see how permanent the changes were.
The reasons for change and the actual/quantitative impact of the changes would have to come from another study. While what the "researchers thought" is interesting, it's not supported by any evidence, i.e. no measurements were taken to see if any of the suggested improvements were present.
FWIW my wife underwent a drastic personality change after giving birth, and I would definitely agree with this being one of the symptoms. But just one data point of course.
As a counterpoint, my wife gave birth to our daughter a couple of years ago and I saw no noticeable personality change. She was perhaps more emotional at first but that seemed as much a result of sleep deprivation as the actual pregnancy and birth.
The part of my experience that seemed relevant to the article:
areas of the brain involved in social interactions used for attributing thoughts and feelings to other people - known as "theory-of-mind" tasks
...was that I noticed she wouldn't differentiate between whether something had actually happened or not. For example, she could get quite angry at someone for something they didn't do, just thinking they "might" do it.
Then again, maybe this personality aspect had been there all along and I had never noticed until the additional stress of having a new baby.
EDIT: Please don't downvote me for answering a question.
I really don't want this to come across as rude, because I don't mean to single you out or invalidate your experience (or your contribution to discussion!).
That said, what is the purpose of offering your anecdotal experience if you acknowledge that it is an n=1 datapoint? I understand that it's in good faith to acknowledge that your personal experience doesn't offer any statistical rigor to an interpretation of the foregoing article, but in my opinion your comment primes other readers in the discussion to subconsciously accept certain interpretations that aren't justified by the research. The main takeaway of your comment is "For what it's worth, I have an anecdote confirming an interpretation of the data that is not presented in the original study", and while you follow it up with the anecdote-acknowledgement, the "damage is done" so to speak. You've already opened Pandora's Box with regards to your subtle confirmation of the unsubstantiated interpretation.
In my experience it takes conscious effort not to allow anecdotes to impact interpretation of data, and while I don't think you're doing it purposefully, I believe it's counterproductive to the parent comment's point to offer an anecdote to the discussion while simultaneously acknowledging that the anecdote does not in any way prove the interpretation.
Because this is Hacker News, not the Journal of the American Medical Association. It's a community, and since it's acknowledged by the poster not to be a scientific observation, I'm not sure he needs corrected on it.
That's a fair point, and maybe I'm just demonstrating a personal bias for a particular type of discussion that isn't reflected on Hacker News. However, I didn't try to "correct" the grandparent commenter so much as show that while an acknowledgement of an anecdote is made in good faith, it doesn't take away from the overall impact on the audience. We may not be researchers peer reviewing the work of colleagues here, but we can still strive for a certain level of scientific literacy and decorum in our discussion.
Stated another way - if this were an article about computer science instead of neuroscience, would you expect the overall discussion to be stronger, the same or weaker compared to this discussion in terms of rigor? Furthermore, would you think that rigor was warranted on this forum (these aren't rhetorical questions, I'm curious)? I understand that disciplines like neuroscience allow us to relate with the science a bit (it's tempting to retroactively interpret our experiences with novel research!) but comments offering anecdotes, even with those expressly accounted for, allow biases to be couched in between legitimate data. I certainly think the grandparent comment would be challenged similarly if this was a psychological study with the current concerns about replication.
> what is the purpose of offering your anecdotal experience if you acknowledge that it is an n=1 datapoint?
What is the purpose of using large-n datapoints anymore when the primary motivation of "research" is becoming less about finding meaningful information and more about getting published (in for-profit, paywalled "journals") so you can get more grant money for your institution?
Haven't you seen the articles in the last year or about little scientific research is even reproducible anymore ? You can just repeat your experiment until you get the results you want to see.
> That said, what is the purpose of offering your anecdotal experience if you acknowledge that it is an n=1 datapoint?
I'm not sure I understand your question...the grandparent of my comment noted an aspect of the article, someone replied to that casting doubt, and I replied (that fwiw) I had observed similar behavior.
Historically one couldn't draw conclusions without an exhaustive study, does that now also apply to anecdotes on forums? I've read hundreds of anecdotes on HN so far this morning, are all of those inappropriate?
> Historically one couldn't draw conclusions without an exhaustive study, does that now also apply to anecdotes on forums? I've read hundreds of anecdotes on HN so far this morning, are all of those inappropriate?
In a word, yes.
I'd push back on the word "inappropriate" specifically though. Whether they are inappropriate is a matter of context; in the context of a discussion about a study published in Nature Neuroscience, an anecdote that supports a causal relationship between the research and unsubstantiated interpretations of the data is inappropriate, in my opinion.
I think the disconnect here is a difference of approach - I am approaching this discussion as one of analysis, while there are other commenters approaching this as a friendly conversation. There's no right or wrong there, but I feel compelled to point out that the latter approach is how biased data frequently becomes parroted without real support in the original research.
In your original comment, you mentioned that your wife exhibited a significant personality change that appears to match the article. You also point out that you realize this is an anecdote. However, there is research[1][2] that demonstrates people will begin to internalize what they continually read, regardless of whether or not they know it is not true. In a discussion about a loaded topic such as pregnancy, where people are commiserating with each other or exchanging anecdotes, my claim is that it is not merely enough to acknowledge that the anecdote doesn't represent datum. Rather, that will not do anything to prevent the anecdote from having a positive impact on the audience's impression of the research (positive here used in the dialectic sense).
Of course, I'll admit I'm a stickler for this. Whether or not this is a point worth making in subsequent threads is up to the HN upvote/downvote roll :)
Ah ok, I see where you're coming from now. It is a valid point, but then at the same time I'm a stickler for suppression of free speech, so some sort of a meta-discussion was inevitable wasn't it! :)
As long as people realize it doesn't prove anything, there's still some value to it. Sure, it's not following proper scientific methods, but HN comments are not for peer-reviewing scientific findings. Sometimes, readers may benefit from having a conversation with a human behind that n=1 data point.
Seems logical: a temporary "this isn't the time to think about the needs of your extended family" signal lasting just up until the point the kid can toddle around would be survival enhancer.
By being less able to read into the multiple possible reactions of a person; e.g.
- "they're looking at my baby because she's cute"
- "they're looking at my baby because they want to kill him"
- "they're looking at my baby to feign interest in my life"
...the mothers are able to focus on the important options:
- "they're probably a threat"
- "they're probably not a threat"
While this would be a good followup study, I want to call out that it's not supported in the original research whatsoever. Presently, it's just speculation based on which areas of the brain are impacted by the grey matter alterations.
Following that argument then simple-minded businessmen or people with a Manichean world-view should be great at taking care of babies, since they make quick judgement calls?
That's a function of how well calibrated are those judgement calls with well-being of the baby.
Soldiers who make quick judgement calls are better than ones who don't; but they're trained to have their judgement properly calibrated with the task at hand.
You're not missing anything. As user joncrocks comments in this subthread, the actual study[1] does not do anything other than measure the structural changes. The "why" of the grey matter alterations (which appear to primarily occur in the prefrontal cortex and hippocampus regions) and their resulting impacts are not quantified at all beyond offering hypotheses for future studies.
It is disingenuous to call these alterations "improvements" and any attempt at extrapolating the results to real-world improvements in e.g. perceiving threats in strangers is complete speculation. There simply isn't any material in the research to justify labeling these changes as positive or negative.
The authors do give a few good-faith remarks about how these changes could improve e.g. facial recognition (for a certain subset of defined metrics to satisfy "improve", of course), but there isn't actually evidence to support this. It's conjecture based on what we know of the brain.
What we can reasonably say based on this research is that women experience grey matter reductions after pregnancy that may have an impact on their executive and social functioning skills (if we extrapolate from the specific areas impacted in the brain). Obviously, this depends upon the statistical rigor involved in the study's interpretation as well, but I'm not going to comment on that.
As a meta point, this study is another disappointing demonstration of the way in which the media frames legitimate studies and primes scientific discourse. It is excellent research that stands on its own, and a great contribution to neuroscience at that. There is no need to color the results with speculation, which is cleverly couched between actual results in an optimal context. My partner brought this study up with me at dinner last night, as it had already started making the rounds. Naturally, when I asked her for concrete examples of these "improvements" and how they were supported by the study, she couldn't offer any, and was annoyed by my questioning. Not only did the articles do an intellectual disservice to her (and others!) by priming her expectations with illegitimate results, they encouraged a "pre-chewed" version of the study that would not hold up to real challenge or inquiry. I subscribe to Nature (and many of its subjournals), and I absolutely refuse to read scientific literature from secondary sources if I can find the study. But this isn't a reasonable expectation for everyone; in a world where most people aren't going to click through to read a 4 - 20 page study, this sort of coverage diminishes the general public's appreciation of scientific results at best, and encourages dangerous interpretations of legitimate data at worst.
I had the baby while at university, and it's true. While I was always brilliant in math and physics, I couldn't do simple things anymore. That was very frustrating. Thanks god the physics professor was very forgiving as he noticed the change
It was probably more about sleep deprivation, chronic stress, and immediate reprioritization in your life, more than anything. It's hard to focus on learning new tasks when you're tired, and you're forced to confront a million new things at home.
The study just said that, in small areas of the brain, gray matter was reduced, and they theorized that this specialization helped a new mother recognize her infant and its needs. Nothing to do with math and physics.
I don't know much about the reality of 'baby brain', but in the study under discussion the researchers tested cognitive skills like memory, verbal skills, and working memory, and there was no significant change over time. It looks like the after-pregnancy tests were given late enough that kids were probably sleeping through the night (or at least in 5-6 hr chunks).
I have to say I don't think the article supports that at all. The study looks at a 2-year stretch and the changes in all but the hippocampus are still there at 2 years. Even friends who have reported "baby brain" don't claim it lasts 2 years, and synaptic pruning is not correlated with feeling foggy in any other study (and there have been a bunch!).
Pregnancy raises at least estrogen and progesterone to something like ten times the usual menstrual cycle peak, so I doubt the effect size is comparable. Also, I think pregnancy affects a broad range of hormones, not just the handful in birth control.
Oxytocin levels also increase. That would be the first one I'd test for -- if there was a correlation between oxytocin levels and extent of grey matter loss.
Otherwise we'll project unrelated biases under the guise of science. Otherwise we risk unconsciously ignoring or lessening the relevance of facts that contradict those biases.
There's nothing sexist about studying the differences between male and female and learning about the biological/physiological strength and weaknesses of each. But there's little scientific justification in extrapolating that to unrelated conclusions.
Edit: Not to mention the fact that we know very little about the brain compared to literally any other internal organ, so attempting to draw conclusions about behavior or sociology based on changes in the brain in some women during pregnancy is probably a fool's errand.
It isn't sexist to study sexual dimorphism. It would be sexist to have a conclusion about the sexes and then cherrypick evidence to support it- but finding evidence and then drawing a conclusion is in no way sexist.
Note that this study shows significant and multi-year structural changes between women who have experienced pregnancy and birth and women who did not conceive or give birth during the same time period. This is not a study that is primarily about differences between the sexes.
Why? What's the danger here, that you'll be wrong? If you interpret the differences "with caution" are you more or less likely to interpret them correctly?
Does the percentage of mothers who were getting fertility treatment make this actually representative? The pain and suffering that those who struggle to have children followed (presumably!) by happiness when they have a child must have some effect?
The average age of the participants also seems high to me, but a brief search for an average age for having a first child put this study cohort only slightly over that - surprising to me at least.
Baby blues and postnatal depression are common, even among people who've been through fertility treatment. Indeed, those people may find it harder to seek help because of the assumptions that they must be happy after all that struggle.
(Also, about 1 in 10 men have postnatal depression.)
This is true, but two years down the track one would hope this had passed. I know that long term health problems do occur but I don't think anyone would describe them as post-natal depression or baby blues at that point.
It's a bit surprising that a Nature Neuro paper didn't have more control groups. But on the other hand, it's trickier to get ahold of first time adoptive mothers etc. And on the third hand, there's always somebody requesting increasingly specific control groups and one just has to stop and publish at some point.
Similar to open sourcing "ugly" code. At some point the benefit of releasing is worth putting out non-perfect work. If there's interest, someone can build on what you've done and fork your progress.
I always wonder about claims like this from both sides. I see people claiming pregnancy alters a woman's brain, miscarriages can cause postpartum depression, but then see claims that abortions do not effect the brain at all. The third I find hard to believe given the first two. And I know this is a touchy topic, but I am pro-choice yet find it a bit baffling that we ignore some of the science behind its effects on the brain and moods. Hormones are very powerful. If you are on either side of that fence, I think we can all agree that we want the woman to be well. I feel like writing off effects for political reasons does nothing but damage women (I think this is more U.S. than other countries.) Especially if we consider some women getting abortions are doing so for socio-economic reasons. If their brains are effected (they become depressed,) that is hurting their social standing even more. If we can identify that as a possible effect, then we can treat them.
A bit of a tangent, but it's something reading this prompted me to rant about.
The only thing I've read about the subject says that women who have abortions are happier and have better mental health in the long term than women who were denied an abortion. So the study isn't "women who have never been pregnant" vs. "women who had an abortion," but the headlines can sometimes make it seem that way. "Abortions are great for mental health!"
Also, according to the CDC, two thirds of abortions happen within the first two months of pregnancy, and 92 percent within 13 weeks. When we think of devastating/traumatic miscarriages, those are generally later. Many women miscarry without even knowing it.
If I had to hazard a guess, I would say that the "average" number of weeks at which women miscarry is somewhat lower than the "average" number of weeks at which women voluntarily abort a pregnancy, although there is a long tail to the left at which spontaneous miscarriages/stillbirths happen, causing higher rates of depression and/or hormonal complications. Also, there's the non-negligible effect of actually wanting a baby, vs. not wanting to carry a child -- it can have a profound effect on how your body reacts.
I've not actually seen anyone claiming that abortion has zero effect (though I assume you must have seen some such claim). What I have seen are denials that it causes long term depression, which is perfectly compatible with your points about pregnancy/miscarriage. But it's also the question that matters--if the comparison is miscarriage/giving birth, the question is whether it produces any excess psychological effects.
> I see people claiming pregnancy alters a woman's brain, miscarriages can cause postpartum depression, but then see claims that abortions do not effect the brain at all. The third I find hard to believe given the first two.
The reason a miscarriage can cause depression while an abortion usually does not is because the former is against a women's will and the other her choice. I find that quite obvious to be honest.
I am not an expert but I don't think postpartum depression happens because people consider all rational possibilities and conclude that depression is the most logical option. It happens to them because of physical changes during and after pregnancy. It's not like they can just will away those physical changes, or rationalize their way out.
Kind of like how with other types of depression the sufferer can intellectually understand why there is no reason to feel the way they do - but they still do.
My wife and I both took our Professional Engineering Exams (8 hour test that is brutally hard) and she was 6 mo pregnant and still passed while I failed. I really feel dumb now.
How does this research imply that there's any effect on a pregnant woman/new mother's ability to take a PE exam? The study talks about a gray matter reduction in small areas of the brain associated with social interaction. Based on other experiments, they further theorized that this may be a tool to help the mother quickly recognize her infant and assess its needs. Has nothing to do with engineering...
It doesn't. I poorly skimmed it too quickly. She probably had 20+ coworkers tell her she would fail due to pregnancy-brain though, so it was nice to see her pass lol.
I am genuinely not trolling, just curious coz I'm new here: what does this have to do with software? Or does HackerNews cover more than just software? Genuine question, not rhetorical
On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
> On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
I think kegamine is pointing to the grammatical oddity of using the singular "woman" in the title, rather than the plural "women":
Pregnancy alters woman's brain
The article introduction phrases this in a little more concise a way:
Pregnancy reduces grey matter in specific parts of a woman's brain
I can see how the introduction probably became contracted to form the title, but in the contracted version, the plural "Pregnancy alters women's brain" would seem a little more grammatically precise than "Pregnancy alters woman's brain".
Not trying to split hairs but is the study statistically significant that they can safely generalize to all women? Regardless I think the phrase "some womens'" would have been better in the title.
On HN we frequently ask for titles to be altered for accuracy. I would expect a BBC journalist to understand the difference between singular and plural. "Woman's brain" and Women's brains" have different meanings, at least for this speaker of English.
[1] http://www.nytimes.com/2016/12/19/health/pregnancy-brain-cha... [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2475802/ [3] https://scan.oxfordjournals.org/content/10/3/327.abstract