No, new study does NOT show that Cesarean born children have cognitive delays

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Another day, another poorly done study that claims to show that C-sections are harmful.

According to The Sydney Morning Herald, Caesareans linked to slower start at school: research.

[pullquote align=”right” cite=”” link=”” color=”” class=”” size=””]The authors fail to control for the most important confounding variable, the risk that the infant sustained brain damage before birth.[/pullquote]

Children born via caesarean appear to lag behind their peers – who were delivered naturally – in school tests, new research has found.

While the gap in test scores is small, University of Melbourne researchers say it’s equivalent to a grade 3 student missing up to 35 days of school.

And they suspect different bacteria in the guts of babies delivered by caesarean could be behind the delay.

In fact, the study showed nothing of the kind. Indeed, it showed nothing at all for three important reasons:

  • The authors didn’t correct for the single most critical confounding variable, oxygen deprivation.
  • The effect size was tiny.
  • The claim that the microbiome of C-section babies differs from that of vaginally born babies has been debunked.

As a result, the paper does not support the claims that the authors made.

The paper is The relation between cesarean birth and child cognitive development published in the journal Scientific Reports. It was written by two economists and a basic scientist who investigates neurophysiology.

Across several measures, we find that cesarean-born children perform significantly below vaginally-born children, by up to a tenth of a standard deviation in national numeracy test scores at age 8–9. Estimates from a low-risk sub-sample and lower-bound analysis suggest that the relation is not spuriously related to unobserved confounding. Lower rates of breastfeeding and adverse child and maternal health outcomes that are associated with cesarean birth are found to explain less than a third of the cognitive gap, which points to the importance of other mechanisms such as disturbed gut microbiota. The findings underline the need for a precautionary approach in responding to requests for a planned cesarean when there are no apparent elevated risks from vaginal birth.

Where did the authors go wrong?

In any study, it is critically important to ensure that the two groups under study do not differ in any meaningful way from each other. For example, many breastfeeding studies produce spurious results because children who are breastfed differ economically from those who are not. The purported health benefits of breastfeeding are therefore likely to be benefits of being wealthy (which we know has a significant impact on health), not of being breastfed.

In this study, the single most important confounding factor that must be taken into account is brain health at birth. That’s why most studies that compare C-section babies to those born vaginally take care to limit the C-section group to non-emergencies. Emergency C-sections are typically performed for fetal distress presumed to be caused by oxygen deprivation. Therefore, the C-section group is almost guaranteed to contain some babies who have been harmed by lack of oxygen. Restricting the C-section group to elective surgeries limits that possibility.

The authors in this study corrected for nearly two dozen variables:

The analysis includes over 20 confounders grouped into two main categories (Table 1): those related to perinatal risk factors and those related to the socio-economic advantage associated with cesarean-born children in Australia. Perinatal risk factors include the taking of medication during pregnancy for blood pressure or diabetes (proxies for pre-eclampsia and gestational diabetes respectively), the taking of antibiotic medication (a proxy for bacterial infection, which may also affect the development of the infant’s gut microbiome); a dummy variable for low birth weight (coded 1 if less than 2.5 kg; 0 otherwise); weeks of gestation; maternal age at birth; dummy variable for multiple infant pregnancy; length and head circumference of baby (z-scores); dummy variable for whether the baby was conceived using IVF treatment and a gender dummy. We include taking antibiotic medication as a control because it has been associated with changes to the infant’s gut microbiome and possibly the risk of cesarean birth, which means failure to control for it will lead to bias due to unobserved confounding.

Yet they fail to control for the most important confounding variable of all, the risk that the infant sustained brain damage before birth. Since the authors can’t be sure that the babies in each group were cognitively equivalent at the outset, they can’t conclude that observed cognitive differences were due to C-sections.

A second factor undermining the authors’ claims is that the difference in cognitive ability was extremely small. The effect size was less than 0.1 standard deviation.

What is effect size?

The article It’s the Effect Size, Stupid; What effect size is and why it is important explains the difference between statistical significance and effect size:

‘Effect size’ is simply a way of quantifying the size of the difference between two groups. It is easy to calculate, readily understood and can be applied to any measured outcome in Education or Social Science. It is particularly valuable for quantifying the effectiveness of a particular intervention, relative to some comparison. It allows us to move beyond the simplistic, ‘Does it work or not?’ to the far more sophisticated, ‘How well does it work in a range of contexts?’ Moreover, by placing the emphasis on the most important aspect of an intervention – the size of the effect – rather than its statistical significance (which conflates effect size and sample size), it promotes a more scientific approach to the accumulation of knowledge. For these reasons, effect size is an important tool in reporting and interpreting effectiveness.

In this study, the effect size was less than 0.1. How do we interpret that?

Another way to interpret effect sizes is to compare them to the effect sizes of differences that are familiar. For example, describes an effect size of 0.2 as ‘small’ and gives to illustrate it the example that the difference between the heights of 15 year old and 16 year old girls in the US corresponds to an effect of this size. An effect size of 0.5 is described as ‘medium’ and is ‘large enough to be visible to the naked eye’. A 0.5 effect size corresponds to the difference between the heights of 14 year old and 18 year old girls. Cohen describes an effect size of 0.8 as ‘grossly perceptible and therefore large’ and equates it to the difference between the heights of 13 year old and 18 year old girls. As a further example he states that the difference in IQ between holders of the Ph.D. degree and ‘typical college freshmen’ is comparable to an effect size of 0.8.

So an effect size of less than 0.1 is tiny and therefore, not particularly meaningful.

Finally, the authors offer an explanation for the purported difference between C-section babies and vaginally born babies that has already been debunked.

According to the authors:

The direct association may occur through alterations to the infant’s gut microbiota. Unlike vaginally-born children whose gut is seeded by passing through the birth canal, the gut of cesarean-born children is seeded through contact with the mother’s skin and hospital surfaces. The result is long-term compositional differences in gut microbiota by mode of birth with differences observed up until age seven…

There is absolutely nothing in this study that gives credence to this explanation, and the authors acknowledge that this theory has yet to be proven in any context:

Although causal impacts on child development are yet to be proven, altered signaling from disturbed gut microbiota is thought to be a possible driver of higher rates of cognitive disorders, especially autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), among cesarean-born children …

In addition, a larger, more recent study has debunked the theory that the infant microbiome differs appreciably between C-section and vaginally born babies. The newer study concluded:

[T]here was no discernable effect of the cesarean mode of delivery on the early microbiota beyond the immediate neonatal period (and never inclusive of that in the meconium or stool) …

The bottom line then is that there is NO EVIDENCE that C-sections lead to cognitive delays.

Any study that claims to show that C-section babies have cognitive delays must correct for hypoxic birth injuries, have a moderate to large effect size and be based on a plausible biological mechanism.

This study strikes out on all three counts.

123 Responses to “No, new study does NOT show that Cesarean born children have cognitive delays”

  1. Seeing Clearly
    September 15, 2017 at 3:15 pm #


    • FortyMegabytes
      September 15, 2017 at 3:40 pm #

      I was going to dismiss everything you said, but that fact that you posted it in allcaps has persuaded me. It clearly shows your thoughtfulness, openness, and level of rationality.

      Please, continue to use similar methods in all your future attempts at persuasion. I can guarantee everyone else will see your arguments the same way I do right now.

    • Chi
      September 15, 2017 at 4:01 pm #

      Wow, for someone who claims to be so ‘educated’ you really are showing a lot of ignorance.

      I invite you to go and take an actual BASIC chemistry class and learn the difference between an element and a compound. Also, aluminum is one of the most abundant metals on earth. It’s in everything so this panic about it is completely unfounded.

      As for the rest of your spiel….wow. You might want to tighten your tin-foil hat. If you’re not careful it might slip and then the ebil lizard overlords will beam ideas into your brain.

      • Dr Kitty
        September 15, 2017 at 6:32 pm #

        No tinfoil hat. Tinfoil has aluminium in it…

      • Sue
        September 18, 2017 at 2:33 am #

        And one of the most common sources of aluminium absorbed into the blood stream of babies? Breast milk.

        (Before any anti-vax numpty comes back with “ingested is not the same as injected”, they both result in absorption into the blood stream – and excretion by the kidneys).

    • Roadstergal
      September 15, 2017 at 4:40 pm #

      All caps, now? Come on, it’s _gotta_ be a Poe.

      • Azuran
        September 15, 2017 at 7:40 pm #

        If it’s one, that dude has a lot of commitment, considering he has a youtube channel peddling more of his crap.

      • Nick Sanders
        September 16, 2017 at 11:07 am #

        That’s the thing about Poe’s Law, there is no position so extreme and nonsensical that someone does not hold it…

      • Empress of the Iguana People
        September 17, 2017 at 6:11 am #

        it does make for an interesting change from his thesaurus abuse in his first few posts.

    • September 15, 2017 at 5:35 pm #

      Gotta love how “liberalism” is a moral flaw in the same vein as deception/lies, cowardice, and hypocrisy. Because that’s not a “rape, murder, and jaywalking” argument … even assuming that I think there is anything wrong with liberalism as a political philosophy, which I don’t.

      I mean, hell, you even fucked up on the ADHD drugs. They’re amphetamines, not cocaine. If you’re going to be peddling misinformation and lies, maybe try not to sound quite so ignorant about the basics of everything?

    • Empress of the Iguana People
      September 15, 2017 at 6:15 pm #

      Bless you, dear. Maybe you should go volunteer at the local afterschool program and help keep an eye on all the energetic kids?

      • Chi
        September 16, 2017 at 9:05 pm #

        Oh god no. We don’t want this moron peddling his crap to easily influenced youngsters.

    • Azuran
      September 15, 2017 at 7:38 pm #

      Dude, I don’t know what you’re snorting, but I want some.

      • Heidi_storage
        September 16, 2017 at 7:31 am #

        I dunno, seems like a bad trip.

      • MaineJen
        September 16, 2017 at 8:30 am #

        It’s nothing but the raging sexual frustration of the continually repressed.

    • momofone
      September 16, 2017 at 7:30 am #

      Oh honey. Bless your heart. I hope that when you grow up you’re able to get some air. And some punctuation.

    • MaineJen
      September 16, 2017 at 8:26 am #

      Good lord, are you still here? And you’ve graduated to all caps, I see. Very effective way of making your point.

      You are horrified by what you see here, and yet you keep coming back. Why? Surely it can’t be some misguided desire to convert the heathen. Most of the posters here have 20 years or more on you, you’re not going to make a dent with your ‘logic.’

    • The Bofa on the Sofa
      September 16, 2017 at 10:09 am #

      Yeah, I remember when I had my first beer….

    • Mac Sherbert
      September 16, 2017 at 4:10 pm #

      I don’t agree with all of Dr. Tuteur’s political views, but I’d not call her a coward.

      • Who?
        September 17, 2017 at 1:25 am #

        I think SC thinks it is cowardly to try to make the best of it for someone who suffers from autism, ADHD or whatever else he rails against, rather than going with his preferred response: wailing, keening and rending ones garments, in between blaming the lazy and vicious mother responsible.

    • StephanieJR
      September 17, 2017 at 10:23 am #

      Well buddy, since you’re such a persistent little shitstain, I’m going to try a different tactic.

      Picture in your head a seventeen year old girl. She is sweet, and kind, and brave, a social butterfly, with her whole life in front of her.

      Now picture her life tragically cut short. Picture her bleeding out in a parking lot, shot in a horrific act of violence.

      You don’t need to picture it; her name was Ava Le’Ray Barrin, a black, trans* teenager, killed this year in June.

      She was just seventeen. The youngest transwoman murdered in the USA.

      And now I want you to tell me that a child is abominable. That this lovely young girl deserved to die.

      I want you to sit there and justify her murder. That her mere existence is so offensive to you that her death was something to celebrate. That she is less because of who she was, that she was subhuman and needed to be exterminated.

      I want you to look to her parents, and tell them to be glad that their baby was murdered.

      I want to see how low you can stoop; to reveal just how ugly and inhuman you truly are. If you have no ounce of sympathy, of empathy, you are truly monstrous and borderline sociopathic.

    • Platos_Redhaired_Stepchild
      September 17, 2017 at 11:37 am #

      Turn off the capslock & seek psychiatric help.

    • Sue
      September 18, 2017 at 2:30 am #

      Wow – had to cover my ears from all that shouting.

      It’s always good when people drop posts like this – it shows readers the mentality of the anti-scientists. (Either that, or it’s some twelve-yr-old having fun trolling the grown-ups).

      • Empress of the Iguana People
        September 19, 2017 at 7:55 am #

        This one is a high schooler, so 15 yo troll

    • The Vitaphone Queen
      January 11, 2018 at 3:52 pm #

      Cocaine? Normal? For children with ADHD? What in blazes do you mean, Seeing Clearly Through Ableist Glasses?

      I know, this was four months ago. But still…

  2. MaineJen
    September 15, 2017 at 11:01 am #

    One tenth of a standard deviation?

    Bwahahahahahahahaha 🙂

  3. anh
    September 15, 2017 at 9:11 am #

    “the taking of antibiotic medication (a proxy for bacterial infection, which may also affect the development of the infant’s gut microbiome”

    if they made a point to correct for this, does this indicate that they’d already decided ahead of time that gut biome would play a role in future cognitive outcomes?

    • Sue
      September 18, 2017 at 2:34 am #

      And also implies that the antibiotics used for routine infections generally cause long-term changes – they don’t.

  4. MI Dawn
    September 15, 2017 at 7:33 am #

    Do they use Apgar scoring in Australia? Because, to me, that’s one glaring omission. They do not report any Apgar scores – and I’d expect to see lower scores in a c-section for fetal distress, at least at 1 minute – and that would give a very good indicator as to the reason for the c-section.

    • Robyn
      September 17, 2017 at 5:33 am #

      Apgar scores are standard practice here in Australia. I think the people who prepared this study had very limited access to actual data.

  5. Robyn
    September 15, 2017 at 2:37 am #

    This study measured the children’s academic achievement based on the NAPLAN test, which is a literacy and numeracy test administered to all kids in Australian schools a in years 3, 5, 7 & 9. The test it self is a bit dodgy – usually it just shows what socio-economic group the child belongs to, and how much the school they attend teaches to the test ( rather that letting kids learn stuff that is interesting or useful), Absolutely no data about the childs’ health or birth is collected with the test ( just age, school, languages spoken at home and whether the child is Aboriginal/Torres Strait islander. ) The Federal government, which collates the results, would be highly unlikely to release results from individual children for a “study:” of this kind, so I assume the whole thing was based on parent reports: i.e “how was your child born? what was their Naplan result? This has to make the study very suspect indeed.

    • September 15, 2017 at 3:09 pm #

      I’m also willing to bet that 1/10 of a standard deviation is within the error measurement of the test itself.

      Even the rare excellent standardized test isn’t that accurate in terms of measurement of something as broad as subsets of math skills by 8-9 year olds.

    • Mac Sherbert
      September 16, 2017 at 4:12 pm #

      Ah, sounds much like testing in the States.

  6. Julia
    September 15, 2017 at 12:59 am #

    Oh FFS. I have a sample size of 1 showing that babies born via C-section test above WA state average on both reading and Math. Maybe I should write my own paper. Junk science to try prove an ideological point is infuriating.

    • BeatriceC
      September 16, 2017 at 11:42 am #

      I have a sample size of three showing that vaginally born children are more likely to get into legal trouble (long story, all sorted out) than CS born children. Perhaps we can coauthor a paper.

      • FormerPhysicist
        September 16, 2017 at 12:47 pm #

        Can I join in? My sample says that test scores for c/s born are below average and then dramatically increase to 90th percentile with therapy. No need to mention the therapy is for test-taking anxiety and strategies, we can let them think it’s rebirth therapy or some such.

        • N
          September 16, 2017 at 2:30 pm #

          Would it help to go international? Sample of 3 cs from middle Europe. One has an IQ around 130, one does very well at school until now and one will be a singer when he grows up. Not even 3 years old and he can sing entire books of children’s songs by heart. He could sing before he could talk.

          • Empress of the Iguana People
            September 16, 2017 at 7:04 pm #

            wait, that’s not normal? To sing before you even start solids?

          • N
            September 17, 2017 at 1:16 pm #

            It all depends, if they are born vaginally, it is normal. If they are born by CS, it is probably a vaccine damage. No, wait, oh, I’m confused now. It is so difficult nowadays to tell what is normal and what is the cause of what…

          • Who?
            September 18, 2017 at 5:49 am #

            My friend’s son had little songs for all sorts of things well before he could talk-a song for the car, a song for the pram, a song for bed, a song for going to grandma’s. Quite extraordinary.

          • September 17, 2017 at 4:31 am #

            I also can provide a sample of three, all born by C/S. The oldest of the three is doing so well that he’s taking the entire family (6 adults, 3 children) to Eilat for 5 days, all expenses paid, to a 5 star hotel, after Rosh Hashanah. He’s arriving from NYC tomorrow.

            His siblings are also similar “failures” which must be due to their manner of birth. (Sarcasm)

          • momofone
            September 17, 2017 at 11:06 am #

            But imagine where he could take everyone if he’d been born vaginally!

          • September 17, 2017 at 12:05 pm #

            Nowhere. He’d be dead, and I probably would have been also.
            I was in strong labor for 48 hours without dilatation of even one cm. He weighed over 4 kg, and the doctor told me later that his head was wedged so tightly into the pelvic inlet that vaginal birth was impossible.

          • Janet Madrigal
            September 23, 2017 at 11:02 am #

            I hear you.

            My first boy was an emergency c-section due to occiputal posterior position and resulting foetal distress after extended strong labour (30 hours) with only 1cm dilation. He was 4.3kg and 56 cm long. He was induced and born at 41 weeks. I hemorrhaged after his birth.

            My second boy was emergency c-section after placental abruption at 38 weeks. Apparently it took 3 doctors to pull him out as he was stuck. He
            inherited a large basketball of a head from his father. He was just over 4.8kg and 58cm long.

            My sample size of two passed exams for academically selective high schools and are now studying psychology and economics respectively at university. Frankly, c-sections saved their lives and mine and doesn’t seem to have affected their intelligence.

          • Cat
            September 23, 2017 at 4:42 pm #

            I was a formula-fed, c-section baby and a straight “A+” student. In case you think I’m boasting, I should add that having a more-or-less perfect academic record didn’t translate into a stellar career, nor did it make me a happy teenager or young adult. That’s one reason why I’m not losing any sleep over whether more breastmilk could have made a slight difference to my daughter’s IQ: I hope, for her own sake, that she’ll be good enough at exams to have choices about what she does for a living, and I hope that she doesn’t inherit my crippling anxiety and tendency to depression. That’s about it, as far as I’m concerned.

          • Azuran
            September 23, 2017 at 9:07 pm #

            I hear you. My mother was not abusive or negligent in any way, but due to her own childhood with an abusive father, her constant struggle with mental health problems and financial problems, she had a very limited ability to help us develop any kind of life skills, help us develop and pursue hobbies or help with our developing personality. (We all performed extremely well in school, but life is really so much more than that)
            That’s not something that could have been be fixed with breastmilk and a vagina. And pushing my own kid out of my vagina and breastfeeding her isn’t going to prevent me from making the same mistakes with her.

          • Empress of the Iguana People
            September 24, 2017 at 10:23 pm #

            this is something we worry about, Demodocus and I, since we both have mental health issues and we feel like we suck at teaching our kids the myriad lessons.

          • Janet Madrigal
            September 23, 2017 at 10:13 pm #

            I agree with you.

            My eldest son was very ill for 5 years and almost died in his middle to late teens. He inherited my severe chronic migraines and my husband’s Crohn’s disease. He didn’t attend much of his final 3 years in High School. When he was well he took a bridging course at university to qualify for entry. He turns 23 this year and is in his second year of his degree which he is very passionate about. I think he and all the family are still high on how well he is finally.

            My youngest son has Tourette’s syndrome and has either inherited my depression or developed it due to bullying over the Tourette’s. I’m just hoping they don’t get the family diabetes or my brother’s multiple sclerosis.

            I didn’t breast feed them and I’ve never wasted a minute worrying about that or the c-section either. I care that they are healthy & happy and, lucky for me, at the moment they are.

          • Katie Brockie
            September 18, 2017 at 11:14 pm #

            My sample size of 2 C section babies is that both of them are very successful and smart. One has a philosophy degree and the other is a snowboard instructor living and working in Europe. Plus there’s the whole added “we would all be dead if it wasn’t for the C sections” bonus.

          • momofone
            September 19, 2017 at 7:31 am #

            My one c-section sample size absolutely backs this. (I hope it was clear that I was being sarcastic in my original post, but want to be sure.)

    • Mac Sherbert
      September 16, 2017 at 4:17 pm #

      I have sample of 1 as well. So we can combine them! Ha!
      Anyway, my c-section baby has a gifted IQ and just scored in the 99% in everything compared to both state and national averages.
      Maybe if I had refused the c-section and he had been deprived of oxygen during a breech birth it would have been higher??

      • Sue
        September 18, 2017 at 2:39 am #

        Let’s combine everyone’s story and do a meta-analysis!

    • Box of Salt
      September 16, 2017 at 6:50 pm #

      I’ll add my own n=2 set.

      Sometimes I just want to laugh at the people who buy into the idea that c-section babies will grow up fat and stupid.

      My kids have a better chance at performing well at school . . . because they’re growing up middle class, with educated parents who read to them constantly from birth until they were able to do it well themselves. Their births have nothing to do with it.

      Side vent: my kid who just stated middle school (grades 6 to 8, starting age 11) had to put together a “Snapshot Autobiography” for Social Studies which had to include the birth story. I provided what I thought were the relevant details: where and when. The “when” was pretty much the only interesting part of it, as the docs pulled the kid out exactly on the hour – which was mentioned in the story. Even with that, the birth story was all of two sentences long. Kid got docked points because it was too short. WTF? And what business is it for a middle school teacher to know details of how a kid was born more than a decade earlier?

      • Gæst
        September 16, 2017 at 6:58 pm #

        Wow, that’s just bad teaching. I’d be almost tempted to bring a birth video for show and tell after that. What? You wanted more detail, Teach.

        • Box of Salt
          September 16, 2017 at 7:04 pm #

          Another part of the assignment was selecting one of the stories, and interviewing someone else in the story to compare the kid’s recollection with the other person’s – which I thought was a good part of the assignment.

          But the birth story? That’s something that is absolutely guaranteed to be related second hand. The kid can’t include anything other that was we told the kid about it.

          • Mac Sherbert
            September 17, 2017 at 3:24 pm #

            Sounds like a really bad assignment for foster kids or maybe even adopted kids who weren’t adopted until after they were placed in the system or for a kid whose parents had died.

          • kilda
            September 17, 2017 at 4:48 pm #

            seriously. Both of my kids were adopted from foster care around age 9-10 and we don’t even know who they lived with in their early years, or have a baby picture, let alone a birth story. I would be LIVID if either of them had been given that assignment.

          • EmbraceYourInnerCrone
            September 17, 2017 at 8:13 pm #

            My littlest brother was adopted from foster care. He came to our family at 3, we were not allowed to start attempting to adopt him until he was almost 10. The school made him feel even more separate and different by insisting he write his “legal” name on his school work and not our family name. HE was 5!! If they had done this “birth story” thing to him as well our Mom would have gone even more mama bear on them than she did with the name thing. Schools and teachers really need to be a lot more cognizant of the fact that there are lots of families besides the “traditional nuclear family” with a mommy and daddy and 2.5 birth children.

      • Empress of the Iguana People
        September 16, 2017 at 7:02 pm #

        Some of us have boring stories, others of us are more exciting. Mom always mentioned the raging snow storm and almost having me in the ambulance. :p

    • AnnaPDE
      September 16, 2017 at 7:35 pm #

      My first study of sample size 2 shows that getting a C-section will lead to a PhD later in life inn100% of cases. And a sibling study confirms this, as the CS kid is a heart surgeon whereas the vaginally born kid only managed two master’s degrees. By the standards of this study, that’s definitive proof.

    • Sue
      September 18, 2017 at 2:38 am #

      My C-section born child is currently excelling at a selective high school, including in Ancient History and Latin.

      Before her first vaccine, she could only babble. With every vaccination, her cognitive and motor skills improved. Weaning from BF was also associated with improved milestones.

      Cesarean birth, weaning and vaccination are strongly correlated with steeply improving cognitive function.

    • The Vitaphone Queen
      January 11, 2018 at 3:54 pm #

      This Cesarean baby totally thanks you. 😀 😀 😀

  7. Russell Jones
    September 14, 2017 at 9:03 pm #

    The “gut microbiota” stuff is disturbingly Wakefieldian.

    • Roadstergal
      September 15, 2017 at 2:29 pm #

      I hate misuse of the microbiome – and it’s everywhere. The microbiome is very interesting and there’s a lot of good research around it! However, there’s a lot of research that is utter crap. There are very, very few proven ‘bad’ microbiomes, and a shit-ton of good ones. Studies that see differences in microbiomes, and automatically assign one as ‘good’ and one as ‘bad’ because they wanna, go in my shit pile. (Puns not initially intended, but I’ll pretend they were.)

    • Sue
      September 18, 2017 at 2:40 am #

      Yep – lots of pseudoscience in this area, leading to $$$ from the sale of pro-piotics, dietary advice and other immune-boosting woo stuff.

  8. Casual Verbosity
    September 14, 2017 at 6:06 pm #

    Aaand this is why our p-value myopia is producing BS science.

  9. CSN0116
    September 14, 2017 at 5:10 pm #

    Controls for 20 confounding variables?! What was the sample size? Better have been huge.

    • swbarnes2
      September 14, 2017 at 5:47 pm #

      Looks about 3300 total, but I can’t see how many are in the 8-9 year age group that they say had the finding.

      Also note “Postnatal interventions such as the use of a ventilator and the use of intensive care were not included as controls because they may be considered an outcome of delivery mode.”

      Yeah, sure, a need for a ventilator is totally about birth method, not about underlying reasons for that birth method.

      • Roadstergal
        September 14, 2017 at 5:50 pm #

        I can see the negative feedback loop in effect. Scare women away from C-sections, so they labor longer in order to avoid them, so the C-section comes later after the baby has already been in substantial distress, so any negative effects from distress are attributed to the C-section, which leads to more scary figures mis-attributed to C-sections, so women wait even later when a C-section is indicated, which leads to even worse outcomes…

        • Hannah
          September 15, 2017 at 10:43 am #

          Yes exactly. It’s very, very easy to paint intervention as the villain of the piece when they are only ever encountered in crisis. The natural birth lobby has been relying on this lazy but effective psychology for years.

      • Gæst
        September 15, 2017 at 7:27 am #

        Such a dumb study. My daughter was in fetal distress, and the c-section was done to *prevent* birth injury (or prevent worsening it, since it’s hard to say what exactly was going on in there). But the c-section didn’t cause anything – it didn’t cause my pre-eclampsia that necessitated early induction of labor. A c-section didn’t cause my pregnancy to be twins. The c-section didn’t cause my daughter’s placenta to be small, and it didn’t cause the NICU stay. I have no idea whether my children have slight developmental delays, but they seem fine to me, and the c-section helped to ensure that.

      • Azuran
        September 15, 2017 at 9:25 am #

        Wait, so they only had findings in the 8-9 years old group?

        • September 15, 2017 at 3:31 pm #

          The 8-9 year old group had the most “complete” data sets available – probably because it had the highest attrition rate.

          • Roadstergal
            September 15, 2017 at 3:59 pm #

            It’s true. The fewer rooms my husband walks into, the better I am at cleaning.

      • September 15, 2017 at 3:48 pm #

        That made my head swim for a second because there are actual statistical tests that the authors could have used to determine if the dummy variable for CS was collinear with either ventilator use or ICU/NICU use.

        I started having flashbacks to bad creation science apologia where a person is like “radiocarbon dating is flawed because the ratio of C-13 to C-14 in the atmosphere varies over time!” and I have to reply with “yeah, scientists have thought about that and here’s how they corrected for that….”

        Statisticians have worked out a lot of nifty tests to answer all sorts of tricky research questions like “do these two variables measure the same thing?” Not being aware of that fact doesn’t mean it doesn’t exist.

        • swbarnes2
          September 15, 2017 at 5:32 pm #

          Or I suppose you could have thrown all the kids with NICU time or ventilator time out of the study…but since this is based on parent recall, maybe you’d still have skewed results if parents forgot whether or not their kid was on a ventilator for a few hours?

        • L E
          September 25, 2017 at 12:50 pm #

          Suzanne Harper Titkemeyer’s mouth is my personal toilet bowl.

      • September 15, 2017 at 5:30 pm #

        Wait, what? I missed that the first time around.

  10. KQ Not Signed In
    September 14, 2017 at 4:50 pm #

    My rage is tremendous at this slanderous “study” and it’s spurious “findings.”

    What a load of B.S.

  11. Emilie Bishop
    September 14, 2017 at 4:45 pm #

    Things like this make me so grateful to have been born via c-section. I was breach and overdue, so it made the most sense. I was just fine. So was my younger brother, who was scheduled pretty much as soon as Mom knew she was pregnant. After two early losses before me, then secondary infertility between me and my brother (we’re six years apart), Mom didn’t care how we came out of her, just that we were here. Consequently, I was never inclined toward an all-natural birth and I never viewed a c-section as failure. Failure of my epidural topped my fear list in my final days of pregnancy. A c-section was way down on the list. Stop with the shaming already!

    • BeatriceC
      September 15, 2017 at 4:25 pm #

      Before I ever got pregnant I was a little afraid of a c-section only because it’s major surgery. But after the late term miscarriage of twins and a singleton, plus a traumatic vaginal delivery of a late preterm baby with a shoulder dystocia complication, I was on team maternal request c-section all the way. I refused to even consider another vaginal delivery again.

      • Emilie Bishop
        September 18, 2017 at 11:24 am #

        I’m so sorry for all your difficulties,but glad you found something to allow you and your babies to be healthier.

  12. Heidi
    September 14, 2017 at 4:32 pm #

    I can’t imagine what one would really hope to accomplish with this study anyway. To guilt women who had a c-section and have them second-guess their doctor’s advice?

    Magical breast fluid and magical vaginal bacteria! How do we women even get sick?!

    • LaMont
      September 14, 2017 at 4:40 pm #

      We get sick because we sin against our inner goddesses. Sin is the cause of all illness, unhappiness, etc.!

    • Amy Tuteur, MD
      September 14, 2017 at 7:27 pm #

      What they hope to accomplish was to add a study to their bibliographies; it didn’t seem to matter to them what it did or did not show.

  13. Abby
    September 14, 2017 at 4:00 pm #

    And also even if it was a true finding who cares? A child who died during delivery for want of cesaerian section is not going to have the chance to do well at school, I’d rather have a live child a tiny bit behind than a dead child. It’s a stupid premise from the start clearly trying to push an agenda, less c sections – we want your babies to die in childbirth with their micobiome intact!! Cos you know microbiomes are the most important thing in a baby, not intact brain function or anything trivial like that… idiots

    • kilda
      September 14, 2017 at 4:43 pm #

      can’t have our babies “impure” now can we? kind of like the old idea that women should die resisting a rapist, so as to keep their “virtue” intact.

    • Sue
      September 15, 2017 at 1:52 am #

      If the intra-partum deaths were included in the analysis….not much cognitive function if you don’t survive birth.

    • Merrie
      September 15, 2017 at 9:35 pm #

      They’re just looking for more reasons to campaign for reducing the c/s rate. Since supposedly c-sections are mostly done for frivolous reasons anyway, the way to reduce them is to scare people out of having them by coming up with imaginary problems that they supposedly cause.

  14. Anj Fabian
    September 14, 2017 at 3:50 pm #

    At one point they were working on a premise that women who delivered under private insurance were more likely to have maternal request cesareans and women who delivered under public insurance were more likely to have medically indicated cesareans.

    They provided no citations for those two assertions.

    The whole thing confused the hell out of me. Someone pointed out that the birth information was provided via parent surveys and not via medical records.

    My jaw dropped. Even if you could reproduce this study, who would want to?

    Maybe someone should do it again. Toss out the high risk cohorts – the preemies, the NICU babies, the known birth injuries, the congenital diagnoses that impact cognitive development. (You might want to remove the children diagnosed with autism spectrum disorder too.) Leave only the healthy, full term babies. That way you’d have a nice plain vanilla cohort to work with.

    If you can get medical records, please do. Those are much more reliable than what a lay person remembers years after the event.

    • The Bofa on the Sofa
      September 14, 2017 at 4:08 pm #

      Wouldn’t the way to do it to be to compare breech C-section and/or non-incident repeat c-section vs full term vaginal delivery?

      My older guy was a breech c-section, but was 3 weeks early. Technically full term, but maybe doesn’t qualify. Then again, he doesn’t help, because he’s in the high-ability class in school.

      My younger guy, however, was a RCS and went full term (39+2, I think), so he’d qualify. Then again, he is actually far ahead of his older brother (he’s only in 1st grade, so they don’t have the high ability class option yet, but we don’t doubt he is going to be there)

      • Sue
        September 15, 2017 at 1:54 am #

        I suspect the SOB readership has a higher than average population of kids excelling at school, since the most important factors are genetics and nurturing.

        • Roadstergal
          September 15, 2017 at 2:30 pm #

          Posting on SkOB improves outcomes! Do the study – we know the reviewers and journal to use, now. :p

          • September 15, 2017 at 3:30 pm #

            Well, it actually might improve outcomes lol! People learn a lot about parenting, what does and doesn’t matter as much, parenting techniques, and self-care.

          • Roadstergal
            September 15, 2017 at 3:45 pm #

            Given that the evidence shows that early supplementation leads to greater long-term success breastfeeding, and that this strategy is discouraged by many LCs and generally accepted here – I want to see the study that shows that SkepticalOB readers are more successful at breastfeeding than patients of LCs. :p

          • Amazed
            September 16, 2017 at 7:42 am #

            Are you ready to bear the moral responsibility for all the cases of hysterics and indignation induced asthma? Unfortunately, we’re a bunch who has not had a conscience removing surgery here. You know they will have a fit.

          • Amazed
            September 16, 2017 at 7:40 am #

            Even being related to someone posting on SkOB improves outcomes! My niece – 1 year, 7 months – understands playing tricks. Yesterday, she repeatedly came to my door, hammered down on it and called, “Auntie!” Then, she ran away to hide because there was simply no way for me to guess who this person was. Then, when I would go out wondering, “Did someone call for me?” she would giggle. Stupid, stupid Auntie! Not knowing if someone called for her!

            Of course, she’s this great because she came via the right exit. Smooth birth, genetics, her parents financial state, and the fact that she us very well looked after and paid much attention by everyone has nothing to do with it. It’s her mom’s magical jay-jay and not all the books she’s been hunting for her.

    • Ozlsn
      September 15, 2017 at 7:29 am #

      I would love to know who the reviewers were. I spent about half that going “what?!” and the other half laughing because it was just so bizarre.

    • AnnaPDE
      September 16, 2017 at 7:47 pm #

      The private/public thjn is probably real. Because women know that with a private provid you choose your doctor in advance and according to your own priorities, including the certainty that you can say “oh and btw can you please get the kid by CS, let’s not even try labour” and the doctor will probably say “sure, let’s book the operating room”. In the private system, you pretty much end up with whoever is on duty when you’re coming in, and getting a specific doctor to be there, let alone do a CS for no other reason that you’d like one, is not guaranteed.
      Which is why I happily paid about $5000 in doctor’s fees to get the doctor I really wanted in the hospital that happens to be 10min from home, and who specialises in CS.

  15. mostlyclueless
    September 14, 2017 at 3:28 pm #

    Apparently the journal Scientific Reports accepts p < 0.1 as statistically significant:

    "*p-value < 0.1." <—table 2 caption

    Maybe I should start submitting all my failed experiments there…?

    • mostlyclueless
      September 14, 2017 at 3:29 pm #

      along the same lines, with 11 independent tests the bonferroni-corrected criterion is 0.004. this paper (unsurprisingly) is total fucking garbage. I urge readers in the field to write a letter to the editor to demand a retraction.

      • The Bofa on the Sofa
        September 14, 2017 at 3:39 pm #

        Here’s a dose of reality:

        Statistics aside, I don’t care. If you have to control for 20 friggin confounding variables, the suggestion that you have accounted for them all is nonsense.

        You are really claiming that there are 20 confounding variables and not 21? Or that you have adequately accounted for all of those 20 variables?

        Yeah, I think not….

        • Roadstergal
          September 14, 2017 at 5:48 pm #

          Which brings it back to the effect size. If there were a real-world effect, you wouldn’t need to control for 20 things to get a shitty p-value of a hint of a few days of difference. If you’re digging that hard, either it doesn’t exist, or it’s such a small factor that it’s overwhelmed by all of the other forces. (The Worry About Shite That Matters deal. Smoking is a big one, a risk factor for lung cancer and COPD that’s clear enough to not need any statistical finagling to see. Worry about that. Whether one particular vegetable reduces the risk of a certain cancer a tiny amount isn’t worth worrying about.)

          • KeeperOfTheBooks
            September 14, 2017 at 9:21 pm #

            My FIL is constantly touting the latest odd article he’s read about how to keep from getting sick, or This One Weird Hack type stuff. It all just feeds into his anxiety without actually accomplishing anything for the better.
            Fact is, he’ll live a far longer and happier life if he’d stop freaking out over every tiny little happening in his life (“If this highly unlikely bill passes in the HOA four subdivisions over, OUR HOUSE WILL SPONTANEOUSLY COMBUST!!!”), get 8 solid hours of sleep each night vs a (self-inflicted) couple of 3-hour blocks, and eat a few servings of any fruits and veggies every day.

          • Roadstergal
            September 15, 2017 at 2:32 pm #

            I like canned vegetables. My vegetable intake is way higher with them. Sure, fresh is probably ‘better’ if all else were equal, but all else isn’t equal.

          • KeeperOfTheBooks
            September 15, 2017 at 3:58 pm #

            The way I see it, canned veggies are miles better than no veggies, so if that’s what works, then they rock!
            They also have a much longer shelf life than their fresh counterparts, which is nice if you have limited time for shopping each week.

          • Roadstergal
            September 15, 2017 at 4:00 pm #

            And – well, I’m more likely to buy canned veggies in the first place, because I feel horribly guilty when I throw food away, and I never have to worry about that with canned. 🙂

          • MaineJen
            September 15, 2017 at 4:08 pm #

            I’m so lazy, I eat the “steam in bag” vegetables that you can make in the microwave, because I a) hate cooking, and b) hate doing dishes. Win/win!

          • KeeperOfTheBooks
            September 15, 2017 at 4:18 pm #

            That’s why I buy frozen veggies far more than fresh or canned. I don’t like the taste of most canned veggies, but I’ve forgotten about fresh ones too many times. (Unless it’s asparagus, because I could eat roast asparagus all freaking day and not get tired of it.)

        • Casual Verbosity
          September 14, 2017 at 6:05 pm #

          This was quite telling:

          “Without the possibility for randomization, a common approach for dealing with this form of bias is instrumental variables. This method relies on the presence of factors in the data that affect cognitive development only through altering the chances of cesarean birth. We are unaware of any strong candidates in our data…”

          So they obviously didn’t think it was worth speaking to somebody who might have some kind of an idea about that. At least 5 people spring immediately to my mind: paediatrician, obstetrician, developmental psychologist, neuropsychologist, and anyone with an ounce of common sense…

          • AnnaPDE
            September 16, 2017 at 8:00 pm #

            Anyone who ever had a C-section for a medical reason, too.

        • Azuran
          September 15, 2017 at 9:33 am #

          If you have 20 confounding variables, you don’t need to account for them. You need to burn everything and start over with a better methodology.

        • September 15, 2017 at 3:42 pm #

          Oh, they went one step further.

          Rather than starting the model with all 20 confounding variables* and winnowing the variables out by a reputable statistical testing option, they started with a model that consisted of CS birth + all perinatal risk factors combined + socioeconomic status.

          They then reported out only the CS birth effects. I’m very curious what the effects were found on perinatal risk and SES.

          *Some risk factors that they couldn’t include due to missing data include smoking during pregnancy, current smoking, drinking more than 2 alcoholic drinks per day currently and maternal body mass outside of 18.5-25. They also chose to discard information on use of ventilator or stay in ICU since the authors thought it might be collinear with C-sections…but didn’t do any statistical analysis to support that hypothesis.

      • Casual Verbosity
        September 14, 2017 at 5:59 pm #

        My stats lecturer would have conniptions.

    • Roadstergal
      September 14, 2017 at 3:33 pm #

      0.1. With so many tests done. Where’s the “Shame” woman??

    • mostlyclueless
      September 14, 2017 at 3:38 pm #

      And another thing. Suppose for a moment you believe their ridiculous hypothesis — that cesarean delivery affects cognitive development. Even then, one would have to grant the the size of the effect would get smaller over time, as other developmental influences took effect, no?

      And that does seem to be the case with the “vocabulary” measurement, which decreases in effect size from a coefficient of 0.087 at age 4-5, to coefficient 0.05 at age 6-7, to coefficient 0.047 at age 8-9.

      However, the “problem-solving” measurement shows the OPPOSITE trend — with the effect (of cesarean delivery on cognitive performance) more than doubling, from a coefficient of 0.036 at age 6-7, to 0.069 at age 8-9.

      What’s more believable: that the effect of cesarean delivery on problem solving INCREASES as a child gets older — or that this fishing expedition produced a handful of spurious results through multiple testing without multiple corrections and an unacceptably lenient statistical threshold?

      • September 15, 2017 at 3:17 pm #

        In the US, standardized test creators are cagey about sharing the measurements of reliability on their tests – but I’m very, very skeptical that the testing instrument itself can accurately and repeatedly measure a 1/10th (or smaller!) of a standard deviation difference in math skills in 8-9 year old kids.

        That’s a pretty slim difference in skill levels to pick out using a mass testing instrument. I’m having problems figuring out how I would classify that in a one-on-one unlimited time situation let alone from a multiple-choice test taken by a mass of students.

    • MaineJen
      September 15, 2017 at 11:05 am #

      Again: Bwahahahahahhaaha 🙂

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