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Friday, January 6, 2017

Squishy science: the YOU'RE RUINING YOUR BABY edition

If you've read the barely modified press releases masquerading as news lately, you know that science has found definitive proof that the mere act of being obese destroys your future offspring by causing developmental delays. Yep, a recent study in the Journal of Pediatrics tested thousands of children and discovered that the ones with fat fat fatties for parents couldn't turn the pages of a book or stack blocks as well as the ones with nice healthy stick insects for parents. Proof positive that obese parents produce idiot children with flippers for hands.
Except no, it totally didn't. So there was indeed a study in the Journal of Pediatrics in which researchers looked at data collected by the Upstate KIDS study, which follows 6,000 children in upstate New York. While the children of obese parents were okay with stuff like communication, gross motor skills, and problem solving, it seems that their fine motor skills were delayed compared to kids whose parents weren't obese. But the study has some pretty huge limitations that make it flat-out impossible to draw any conclusion.

First, this is a cohort study. A cohort study is one in which researchers review a whole bunch of data to look for correlations. No matter how good a cohort study is, it can only show correlation. Which might mean there's causation, but might not. The only thing a cohort study can "prove" is that more research is warranted. 

But even for a cohort study, this one has some serious flaws. The sample size is nice and big, but it only looks at kids in a small geographical region. Also, all the data is based on self-reporting - rather than having clinicians in a lab evaluate children, they just have parents fill out a questionnaire. Problem is that self-reporting is a notoriously bad way to get accurate data - people exaggerate, people misunderstand questions, people misremember, people lie. As Wikipedia points out, "Self-report studies are inherently biased by the person's feelings at the time they filled out the questionnaire. If a person feels bad at the time they fill out the questionnaire, for example, their answers will be more negative. If the person feels good at the time, then the answers will be more positive."
Now the researchers say that this effect is mitigated by the fact that the questionnaire that the parents fill out is really specific, but is it? Not really. For instance, the questionnaire asks parents if their kids can turn the pages in a book. That's not a precise question at all. One parent might interpret this to mean a board book, or another, a book with paper pages. One parent might consider the kid incapable if they can't turn the page without ripping or creasing, but another might not consider that a factor. Are we talking big books or small books? Glossy paper or regular? Does the kid spend a lot of time looking at books, and thus get more practice turning pages? Are some parents more likely to give answers based on wanting to make their kid look good? This is the stuff that researchers can control for in a clinical trial, which is what makes clinical trials much better ways to measure this stuff.
And even if there really is a strong correlation, the study has nothing but guesses as to what might cause it. Maybe obesity causes inflammation, which affects the baby's brain development. But that doesn't explain why the dad's obesity would be a factor. Maybe it's not mom or dad's obesity that causes the apparent delays, but the underlying factors causing that obesity. Maybe people with a genetic predisposition toward obesity also have a genetic predisposition to be slightly delayed at page turning. 

So this whole story bugged me for a bunch of reasons. One, I friggin hate it when the media reports on cohort studies like they're the definitive last word. The only purpose of a cohort study is to determine whether further research is warranted, information which is useless to people who aren't scientists. 
And two, yeah, obesity is bad when you're pregnant. It increases the risk of miscarriage, preeclampsia, gestational diabetes, an a whole bunch of other pregnancy complications. Maternal obesity can also harm the munchkin's long term health. We get it. We know now that the whole idea of eating for two is an old wives' tale that's ultimately bad for mom and baby, and we know it's really important to eat healthy and exercise throughout the pregnancy, and don't worry - OBs make sure their patients know it. But eating and exercising are behaviors. Obesity's a state of being that's not easily undone. Ideally, mom's at a healthy weight when she gets pregnant, but life happens. And when articles like these treat more or less wild speculation like scientific fact, it only compounds the guilt and stress that obese moms already feel about something it's too late to fix. It only gives more fuel to the shamers who insist it's okay to treat big women like shit for a situation they already feel like shit over. 
And that's a problem. Because you know what else is really bad for a baby's development? Stress. Such as the stress an expecting mom feels when she's constantly bombarded with hand-wringing articles and finger-pointing editorials. Obese women are stressed enough about the good science - don't try to cause them further stress with bad science.
For the past 20 years since my friends started having kids, I've seen this long stream of the best parents I know beating the crap out of themselves for every parenting mistake, every imperfection, real or imagined. I've talked to pregnant women who feel bullied and shamed by their doctors, their families, or the Internet communities they've turned to for support; who have been made to believe they've screwed up their baby for life before the baby's even born. You want highly inexpert pregnancy advice from a lady on the sidelines? Take care of your baby. But take care of yourself. Listen to your doctor and do your best and love your kid and love yourself and you and your baby will be fine. Because my experience is that the more worried a woman is about this stuff, the less worried she probably should be. 
And for god's sake, stay away from those crazy ass mommy internet forums. Those women will have you convinced that your baby will be born a mutant unless you eat a diet of pure kale juice and give birth directly into a vat of coconut oil and apple cider vinegar. Everybody knows that unless you ALSO feed your baby nothing but Himalayan sea salt goji berries, you might as well just leave it out in the woods to be raised by wolves.

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