This doesn’t tell us the root of the problem (why would feeling less sick go along with miscarriages?) but it does tell us cutting back on caffeine is probably not helpful.
Suppose everyone is subject to the same amount of environmental toxin, and some people react more strongly (by morning sickness, which vomits out those toxins). Then we would expect that the people less aversive to toxins would have more toxins, which would lead to more miscarriage.
In general, morning sickness seems to be good for pregnancy, but I don’t think I’ve seen any evidence that it’s adding good instead of removing bad (but, it would just be weird if it added good, so evidence may have been overlooked).
There’s a very interesting study that finds that parents with more morning sickness have babies with better neurodevelopmental outcomes (20% had IQ > 130, compared to 7% of those with less morning sickness).
The researchers suggest that for some reason the hormone involved in producing morning sickness also aids child development. It’s possible, but a better explanation is the one in your first paragraph—everyone gets exposed to toxins but people vary in how diligent they are in eliminating them, and extra diligence helps.
I’m rather skeptical of this, because it seems that morning sickness eliminates nutrients as much or more than toxins. If the mother can’t keep much down, or only a few select foods, is it likely that the baby is getting needed nutrients? And wouldn’t this effect be as big as the toxin eliminating one, but in the opposite direction?
I’m rather skeptical of this, because it seems that morning sickness eliminates nutrients as much or more than toxins.
Harm and benefit are not equally balanced. If you snarf down some hemlock, the minimal calories you gain from digesting it do not offset the poison you’ve ingested. One bad meal can kill you (the Buddha died of some bad pork, legendarily), but skipping one meal certainly won’t kill you. You would have to skip a lot of meals to equal one bad poisoning episode.
Is there some indication that morning sickness is related to ingesting harmful toxins, now or in the evolutionary past? It doesn’t seem from my experience (close second hand only) that morning sickness is more than increased sensitivity to certain foods, and rather a general nausea that makes many nutrious foods difficult to keep down.
“You would have to skip a lot of meals to equal one bad poisoning episode.”
Suppose everyone is subject to the same amount of environmental toxin, and some people react more strongly (by morning sickness, which vomits out those toxins). Then we would expect that the people less aversive to toxins would have more toxins, which would lead to more miscarriage.
In general, morning sickness seems to be good for pregnancy, but I don’t think I’ve seen any evidence that it’s adding good instead of removing bad (but, it would just be weird if it added good, so evidence may have been overlooked).
There’s a very interesting study that finds that parents with more morning sickness have babies with better neurodevelopmental outcomes (20% had IQ > 130, compared to 7% of those with less morning sickness).
The researchers suggest that for some reason the hormone involved in producing morning sickness also aids child development. It’s possible, but a better explanation is the one in your first paragraph—everyone gets exposed to toxins but people vary in how diligent they are in eliminating them, and extra diligence helps.
Has there been a check on whether the foods which are more likely to cause morning sickness are also more likely to be bad for fetuses?
I’m rather skeptical of this, because it seems that morning sickness eliminates nutrients as much or more than toxins. If the mother can’t keep much down, or only a few select foods, is it likely that the baby is getting needed nutrients? And wouldn’t this effect be as big as the toxin eliminating one, but in the opposite direction?
Harm and benefit are not equally balanced. If you snarf down some hemlock, the minimal calories you gain from digesting it do not offset the poison you’ve ingested. One bad meal can kill you (the Buddha died of some bad pork, legendarily), but skipping one meal certainly won’t kill you. You would have to skip a lot of meals to equal one bad poisoning episode.
Is there some indication that morning sickness is related to ingesting harmful toxins, now or in the evolutionary past? It doesn’t seem from my experience (close second hand only) that morning sickness is more than increased sensitivity to certain foods, and rather a general nausea that makes many nutrious foods difficult to keep down.
“You would have to skip a lot of meals to equal one bad poisoning episode.”
Such as one or two a day for 2-3 months?
http://en.wikipedia.org/wiki/Morning_sickness#Evolution
Morning sickness can get that bad, but it’s rare.
http://www.mayoclinic.com/health/morning-sickness/DS01150