Pregnancy As A Mother/Fetus Battle For Resources
At NEEPS -- the NorthEast Evolutionary Psychology conference this weekend in Boston -- we heard about biologist David Haig's thinking on pregnancy. It's actually well-described by Carl Zimmer in this New York Times piece (though Haig calls himself a "biologist" and not an "evolutionary biologist" as Zimmer does in the piece).
In short, pregnancy can be awfully dangerous to the mother, and Haig doesn't think this is an accident. (Sneaky fuckers, those fetuses.)
Dr. Haig argues, a mother and her unborn child engage in an unconscious struggle over the nutrients she will provide it.Dr. Haig's theory has been gaining support in recent years, as scientists examine the various ways pregnancy can go wrong.
..."We tend to think of genes as parts of a machine working together," Dr. Haig said. "But in the realm of genetic conflict, the cooperation breaks down."
In a 1993 paper, Dr. Haig first predicted that many complications of pregnancy would turn out to be produced by this conflict. One of the most common complications is pre-eclampsia, in which women experience dangerously high blood pressure late in pregnancy. For decades scientists have puzzled over pre-eclampsia, which occurs in about 6 percent of pregnancies.
Dr. Haig proposed that pre-eclampsia was just an extreme form of a strategy used by all fetuses. The fetuses somehow raised the blood pressure of their mothers so as to drive more blood into the relatively low-pressure placenta. Dr. Haig suggested that pre-eclampsia would be associated with some substance that fetuses injected into their mothers' bloodstreams. Pre-eclampsia happened when fetuses injected too much of the stuff, perhaps if they were having trouble getting enough nourishment.
In the past few years, Ananth Karumanchi of Harvard Medical School and his colleagues have gathered evidence that suggests Dr. Haig was right. They have found that women with pre-eclampsia had unusually high levels of a protein called soluble fms-like tyrosine kinase 1, or sFlt1 for short.
Other labs have replicated their results. Dr. Karumanchi's group has done additional work that indicates that this protein interferes with the mother's ability to repair minor damage to her blood vessels. As that damage builds up, so does her blood pressure. And as Dr. Haig predicted, the protein is produced by the fetus, not the mother.
Shitty little ingrate, right from the start.
I'm reminded of Steve Gaulin and William Lassek's research on the bimbo body -- and their finding that women with an hourglass figure and big boobs (and very importantly, hip fat rather than belly fat) seem to be more fertile, to produce smarter children, and to have their children take less from them cognitively during their pregnancy. And yes, depressingly, children do seem to rob mommy cognitively during pregnancy, according to Gaulin and Lassek's work.
Getting back to Haig, he later told me about moss -- that it actually communicates with fellow, uh, mossy bits. I hope he'll come back and present on that next year, and no, I'm not kidding.
It would be interesting to know if pre eclampsia rates are steady across the world's population or if diet/genetics/environment have anything to do with it.
Not blaming a high carb low fat diet, and vitamin d and b deficiencies yet, but until they screen and account for those things, I won't take the research especially seriously.
Since they finally figured out that spinal bifeda was just a vitamin deficiency, about fifty years after they started studying it.
Isab at April 11, 2015 8:43 PM
Fascinating! Doubly so to me as I am about to hit 24 weeks pregnant in a few days. Thank you, Amy for posting this.
N at April 12, 2015 4:57 AM
You're welcome, N. Thanks for the thanks. I'm always jazzed when stuff I post is especially relevant. I find this so fascinating, this mom-fetus conflict.
Amy Alkon at April 12, 2015 6:26 AM
You need to be fair Amy. The conflict is not a one way street but part of an ongoing parent-child conflict that continues after birth. While baby is manipulating mom, mom is also manipulating baby. And both are sharing cells trying to colonize each other.
Oh, and you never get those IQ points back. I used to be really smart. Now ... who knows.
Ben at April 12, 2015 6:45 AM
Interesting. I know one of the handouts from my OB mentions making sure you have adequate protein and fat intake to reduce the chances of preeclampsia. I've never suffered from it, but a few of my friends have. They were all veg or vegan so my guess is they weren't getting enough protein and fat if the handout is correct that eating it reduces the incidence.
BunnyGirl at April 12, 2015 10:04 AM
Interesting. I know one of the handouts from my OB mentions making sure you have adequate protein and fat intake to reduce the chances of preeclampsia. I've never suffered from it, but a few of my friends have. They were all veg or vegan so my guess is they weren't getting enough protein and fat if the handout is correct that eating it reduces the incidence.
Posted by: BunnyGirl at April 12, 2015 10:04 AM
Yes, with decent nutrition there should not be any *battle for resources*, as there should be plenty for both mother and the fetus.
Evolution favors those individuals, and children of mothers who have enough body fat, and take in enough nutrients to give birth to a live healthy baby, and survive the birth themselves.
Isab at April 12, 2015 12:37 PM
No time to go into detail, but in short, Isab's thinking is correct, e.g.:
http://www.mailman.columbia.edu/news/pre-eclampsia-rates-rise-us
There were extremely low rates of 'severe pre-eclempsia' around 1980 and it's been dramatically increasing:
http://www.bmj.com/content/347/bmj.f6564
=> "These trends also seem to be influenced by secular changes in increasing obesity"
We're doing something *else* wrong. Maternal mortality is interesting but complex science. I'm not convinced of Dr Haig's take of there being a 'genetic conflict' - rather, I think it's more likely that pregnancy is simply just an extremely complex and demanding thing, that evolution failed to perfect 100% because it's so ridiculously complex, and evolution didn't 'need to' get mortality rates down to 0 ... 90%+ survival rates were likely just 'more than adequate' throughout our history.
@"Evolution favors those individuals, and children of mothers who have enough body fat"
Unfortunately, while there is some truth underlying this, it seems to have fostered a popular (and incorrect) belief that it's somehow good or healthy or normal to let yourself become obese when pregnant .. it's not, obesity is risky and dangerous and harmful to both mother and fetus. Maintaining just several pounds or so above your 'normal' base weight (+ fetus weight) is probably adequate reserve for your baby as food storage in our 'modern' times where food is not scarce.
Lobster at April 12, 2015 2:17 PM
"Unfortunately, while there is some truth underlying this, it seems to have fostered a popular (and incorrect) belief that it's somehow good or healthy or normal to let yourself become obese when pregnant .. it's not, obesity is risky and danger"
Of course this is true, but few people become obese during pregnancy. Most of these low income mothers start out that way, and there is increasing evidence that most of the obese are also malnourished, because they are eating a diet way to high in carbs, and too low in protein, and essential vitamins.
Isab at April 12, 2015 3:47 PM
My pregnancy was tough. I was an older mother (41) and had mild hypertension (since my 20s-regardless of weight), and overweight. I was trying to lose weight before getting pregnant but hurt my back several months beforehand (and don't have enough time time to postpone).
At about 31 weeks my blood pressure started going haywire. Never had protein in the urine so not completely pre-ecclampsia but I knew that was always a possibility.
We were all lucky that I was able to maintain the pregnancy long enough and while she was born small no NICU stay.
I was lower carb (gestational diabetes) and a carnivore.
Katrina at April 12, 2015 4:13 PM
I'm a relatively low carber as well, and also suffered gestational diabetes with my pregnancies. My pregnancies are complicated by a blood clotting disorder making me high risk, but it's been managed with meds and no problems. I do deliver a little early though. My only major pregnancy problem was with my last. I got pregnant with Paragard in place and they were unable to remove it so it stayed in throughout my pregnancy. I delivered him at 30 weeks due to spontaneous preterm labor they feel was likely related to the IUD. He has a few minor, non-limiting heart defects which may or may not be related to sperm/egg damage from the copper exposure.
BunnyGirl at April 12, 2015 8:05 PM
That's a bit of a one-sided analysis. The baby also does things that improve the mother's health to keep it alive. One of those things is to release what are effectively steroids, that tamp down on autoimmune diseases. My wife has MS and, with both pregnancies, it went into remission and she felt the best she has in the last ten years.
Mike at April 12, 2015 8:27 PM
Weight gain over pregnancy is a fairly individual thing. And it really depends on how overweight you were to start with. Someone who is near their mid BMI can gain 50 lbs while someone who is already 50 lbs overweight may gain 1-2 lbs. The real issue is food quality. As long as you are eating healthily weight gain is a non-issue and you should lose those pounds within a few months of birth. But if those pounds are pringles and french fries losing the weight is much more difficult.
There is another side to this, if the mother tries to limit her weight gain by eating less she often increases the risk of diabetes for her child.
Ben at April 13, 2015 6:49 AM
I was anemic and had gestational diabetes with my last pregnancy. I was eating plenty of meat and certainly wasn't eating an excessive amount of carbs. (I know this because I had to keep a food journal.) I gained a little more than 30 pounds- my non-pregnant weight is around 110. My blood sugar was always highest in the mornings- when I was still fasting. Babies leach the nutrients out of you, and pregnancy hormones influence insulin levels. The baby is fine- she arrived at 39 weeks and was just a tiny bit larger than average.
ahw at April 13, 2015 8:39 AM
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