Quote Originally Posted by lizmonster View Post
It sounds like as long as I've got gravity and enough floating space, the embryo is likely to be OK.

Which brings me back to why things go wrong early on.

I'm still trying to figure out if it's plausible to remove the human factor and get any consistency. I understand sometimes cell division goes wrong, not necessarily for any concrete reason; but I'm wondering if there's some optimal cocktail that will work for embryos that don't go wrong at the early cell division stage, or if that's research we haven't done.

Such research would be a massive ethical minefield, so I know why we don't do it. I'm just wondering how much we still don't know about all this, or if this is a case of "we can't mimic this with machines because X."

Does anybody know why IVF embryos are implanted (or frozen) so quickly? I assume it's because we can't keep them alive outside a maternal environment for very long - but maybe it's an ethical thing?
Well, IVF embryo's are implanted or frozen quickly, because otherwise the quality of the embryo goes down. After fertilizing the eggs, you wait about 3 days before implanting it. You wait about 5 or 6 days before freezing it (because you want to see if the egg evolves into a blastocyst, which not all fertilized eggs will do, and if they don't there's no point in freezing them anyway). With a microscope the embryo gets "graded" to see whether it has a good, average or low chance of ending in a successful pregnancy. You obviously don't want to wait too long to implant the egg, because the implantation takes place only a few days after the fertilization (which, in this case, takes place outside of the womb because of the IVF procedure). If you'd wait a few weeks, for example, the egg/embryo wouldn't have a chance to survive because it needs maternal blood perfusion to grow.

As to your other question: I don't think there's an optimal cocktail that works for all embryos to grow successfully. Yet. Otherwise we wouldn't have failed IVF treatments...
There is a thing called preimplantation genetic screening, which is used to find out if an embryo has a certain severe genetic defect (used in parents that have a high risk of conceiving a baby with such defects). This is still very new, and the only thing I personally know about this in detail is that it is highly controversial. Because in theory, you could abort any pregnancy that doesn't fit your every wish (e.g. you're having a boy when you really want a girl, or something like that). So they are very cautious with this and only use it in high risk couples. But then again, this doesn't guarantee a healthy and successful pregnancy because there's more to it than just the embryonal factors...