How would you categorize pregnancy?

February 17, 2006 10:27 AM

Is human pregnancy symbiotic or parasitic? Contribute to this heated debate among my coworkers.
posted by archimago to Grab Bag (23 answers total)

if you consider the long-term benefits of that kicking beast inside supporting you once social security runs out, symbiotic. if you just consider there's a whole buncha cells in you making you a fattie and eating up all of your food, though, parasitic.
posted by soma lkzx at 10:30 AM on February 17, 2006

You might be a little confused here. Parasitism is a form of symbiosis. (So is commenalism, mutualism, etc).

I think you mean mutualism though (+/+ for both organisms, while parasitism is +/-).

Regardless, the point is that all forms of symbiosis occurs between two different species, so pregnancy can't really be qualified as any form of symbiosis. Pregnancy is in a category by itself.

However, at the heart of your question is if the relationship is good to the mother or not? (I think we can all agree that it is good for the fetus.) If you think about the objective of life, to pass on your genes to the next generations (or to have your children pass on your genes), then human pregnancy (or any pregnancy) is indeed beneficial to the mother as an organism.
posted by ruwan at 10:33 AM on February 17, 2006

A parasite is an organism that

* lives on or in the body of another organism (the host)
* from whose tissues it gets its nourishment, and
* to whom it does some damage

A baby does seem to fit all of the above points, although the damage may be limited to stretch marks and birth injuries. Mutualism doesn't quite fit the bill, either, because while there may be benefits to bearing a child (reduced chances of ovarian cancer, etc.) the child benefits far more from the nutrition and protection of a mother's body.

However, 'parasite' is a charged word. Parasites are rarely taken on by choice or raised to adulthood.
posted by Alison at 10:36 AM on February 17, 2006

Here is the pubmed record for an awesome (quite science-y, though) article about fetal manipulation (and the co-evolved competitive behaviors/physiologies) between mother and fetus. If anyone would like the fulltext, drop me an email. I would say "symbiotic BUT" or "parasitic AND" or more likely "hey it's really complicated and terribly cool to learn about." But then again, I'm not so good at giving easy answers.
posted by unknowncommand at 10:37 AM on February 17, 2006

Well, given that the relationship between bees and flowers is usually characterized as mutualism, I'd have to say this is too. Bees "aid" flower in their reproductive cycle - I've never heard bees characterized as parasites.

It seems (leaving the fact that they are the same species out of it) that this is more strongly the case here - the baby being a very essential component in that reproductive cycle.
posted by vacapinta at 10:40 AM on February 17, 2006

The question starts, I think, with the politically-charged assumption that the fetus is a separate living entity from the mother. While that assumption may not be all that controversial scientifically, the political ramifications may be an impediment to a healthy co-worker debate.
posted by JekPorkins at 10:42 AM on February 17, 2006

I would guess that this has everything to do with the mindset of the mother. If she views the pregnancy as a positive, spiritual, uplifting experience it's certainly a +/+ relationship.

But if she doesn't want to be pregnant, and finds the experience to be an additional weight added to an already burdensome life it's clearly +/-.

The question is rooted more in psychology than physiology.
posted by aladfar at 10:44 AM on February 17, 2006

When my daughter was close to being born, my wife staarted showing signs of pre-eclampsia, and the doctors were taking it really seriously. I later read about how dangerous it coupld have been, and that there was a theory that went like this: The Mother's body is tolerating this foreign object inside her body because of a flood of hormonal signals telling the immune system to leave the baby alone, and in pre-eclampsia, those signals start to fade, and the Mother's body says "get this thing out of me, as soon as possible. Our daughter was a month premature, but fine otherwise. Also, from what I recall, if a mother is undernourished, the baby gets nutrient priority somehow, so it can make things even worse for the mother.

So, my vote would be primarily parasitic, but with an early symbiotic relationship (that can wear out earlier than expected).
posted by kokogiak at 10:46 AM on February 17, 2006

Neither. Unless the debate is just about using these words to mean whatever the debaters "feel" that they mean.

What ruwan said. And isn't another condition of parasitism that the parasitic organism cannot live independently?
posted by desuetude at 11:00 AM on February 17, 2006

"the damage" was my numerous stretch marks aka @ the time (9 mos along) known as the blue highway map
posted by GoodJob! at 11:01 AM on February 17, 2006

It's reproduction. Your child is the same species as you.
posted by mr_roboto at 11:20 AM on February 17, 2006

unknowncommand - props for citing David Haig. I work in the next building over from him and I've heard him give some amazing talks about mother/fetus conflict.

Some interesting genetic conflicts emerge from this - there is sort of an arms race between mothers and fathers. Fathers want to maximize the child's chance of surviving and so want to maximize the maternal resources that flow to the fetus, whereas the mother wants to save some of her resources for future children. So there are paternal genes that try to maximize fetal growth and maternal genes that try to shut those paternal genes down. When things breakdown in this competition you can get some pretty creepy developmental disorders.

PDFs of all his publications, including the review cited by unknowncommand are here.
posted by pombe at 11:22 AM on February 17, 2006

Neither. It's reproductive.
posted by willpie at 11:58 AM on February 17, 2006

pombe that's great! I didn't think to check his site.
posted by unknowncommand at 12:03 PM on February 17, 2006

Speaking as a woman who's had a bit of a difficult pregnancy, it certainly feels parasitic. (Addressing adalfar's psychology vs. physiology theory: This was a planned pregnancy, and I'm absolutely overwhelmed with the the wonders that come with it.)

I have to agree, though, that the parasitic vs. symbiotic thing doesn't necessarily apply. However, the fact that the woman generally does benefit in the long term seems to make it a mutually good thing.
posted by moira at 12:34 PM on February 17, 2006

Agree with mr_roboto and willpie. "Parasitism," "symbiosis," and "mutualism" are used to describe relationships between two organisms of different species.
posted by DevilsAdvocate at 12:35 PM on February 17, 2006

Even if you posit that the fetus benefits more than the mother, this still doesn't feel like parisitism to me. When I think "parasite" I think of something that lives off the flesh of something else. The parasite eats parts of the host that are not meant to be eaten, for example its blood.

In this case, the mother is nourishing and protecting the fetus using specific capabilities of her body that are designed to do exactly that.
posted by alms at 12:44 PM on February 17, 2006

This seems to have gotten bogged down in a debate over terminology, although I suppose that's what the original question was asking about.

The interesting point to me is that regardless of what you call it, the interests of the mother, father, and fetus are not always aligned and so you can get conflicts between them. This is not just interesting per se, but also has some interesting evolutionary consequences.

I wonder what terminology is used by those who study this for a living?
posted by pombe at 12:45 PM on February 17, 2006

Reproduction.
posted by devilsbrigade at 3:33 PM on February 17, 2006

Or, more specifically, "pregnancy" or "gestation".
posted by mr_roboto at 5:04 PM on February 17, 2006

The question is not appropriate. It does not match up in any way to reality. English can be shaped so as to express nonsensical statements and questions. This is one of them. I can ask if Elm trees are more free-market driven or if they are Keynesian. The question is grammatical and can be understood. However the question is not appropriate.

Babies are a result of the normal functionioning of the parent. Babies are neither parasites nor symbiotes, nor commensals, although if you strain hard enough, you can try to make them look like one by seeking overlapping behaviors.
posted by Ken McE at 6:21 PM on February 17, 2006

i've heard it called a virus ... at least that's what i think "the 18 year flu" means ...

seriously, reproduction ...
posted by pyramid termite at 8:48 PM on February 17, 2006

Pregnancy can do a great deal of harm to the mother in many circumstances. If a mother isn't getting enough calcium, the baby will leech calcium from the mother, making the host's/mother's bones weaker. Many vitamin decificencies work similarly in mother's bodies.

However, with some deficiencies, it works the other way. If there isn't adequate food, the fetus will weaken or perish, perserving the mother. With some systems it's the resources that go beyond survival of the mother that get passed to the fetus. Those support the parasite arguement less.

If you disregard the fact it's the same species and it will, in most scenarios, become a mutually beneficial relationship once the child has left the womb, the mother gains little to no benefit previous to birth.

That's a pretty big disregard, though.

When I was pregnant, even at the freakiest, lowest moments, it never felt much like an alien invader, but rather my body was working against me. The mental Us vs. Them didn't occur in my case, even when I knew I wouldn't carry to term, and even when I was (stupidly) watching ROSEMARY'S BABY at month 8. As with all things, Your Mother May Vary.
posted by Gucky at 2:21 PM on February 18, 2006