That's pretty much all that can be said about dizygotic kind of twins, right.? Well, except there is also a somewhat different kind of fraternal twin situation, for which I can find no name except for the name of the uterine condition which can lead to this kind of twin births. This uterine condition is called uterine didelphys, UD, or double ueteri, in which it is posible to get pregnant in each uterus, at the same time or even at different times, and possible to deliver at widely-different times. Two uteri, each half the size of a regular uterus means that at 20 weeks, the baby can begin outgrowing its home. This condition can also result in a single pregnacy or multiples of more than two, dizygotic or monozygotic. Besides the complications caused by smaller uteri, these pregnacies are also at more risk due to higher risk of ectopic pregnancies, as well as labor obstructions caused by having two uteri.
That must be what happened to one of my mom's friends back in the late Fifties: she went into labor & produced two boys--one full-term, the other a 7-month premie.
Oh Perfect Masters,
They thrive on disasters;
They all look so harmless
'Til they find their way up there...
- Brian Eno, [i]Dead Finks Don't Talk[/i]
Well, my head is absolutely spinning with all this information that's new for me, but I think I remember seeing something about the possibility of eggs being fertilized at different times even in single uteri. I might be remembering wrong, though. I'll keep an eye out for that. Interesting, isn't it?
They had to "take" the two babies that shared a placenta. I don't know if they also shared a sac, and won't ask. The parents were told that the two were dying, due to the cords being tangled around them. I know that at least one set of grandparents were somewhat relieved . But the mom feels like she lost two children. That is her new reality. Her body, of course, told her that her reality had changed, that there was one there, changing her and her husband's reality in the way that a forming baby does. No real science needed for that, exactly, it's been going on for centures. And there is still one there. But, being told that triplets were there, seeing them on the ultrasound changed the reality for them even more drastically. Science can do that. Even more real, she had to allow the two to be taken, in order to save the one. And, even though it's still early days yet, mom feels like she has lost two babies.
Yes, I hadn't even gotten to conjoined twins or chimeras yet. Had a couple of tabs up for two interesting situations with chimera, but a storm took the puter down and I lost the tabs. Will look for them later.
Conjoined twins occur when the zygote fails to comepletely separate. Zygotes that separate about day twelve or later after fertilization generally result in conjoined twins. I think everyone is familiar with conjoined twins, so I won't go into more detail, except to point you all to Abigail and Brittany Hensel, Minnesota's beloved and lovely conjoined twins:
