Saturday, December 06, 2008

The stuff you learn about twins

When I found out I was having twins a few weeks ago I knew little about twins. I knew there were fraternal twins and I knew there were identical twins. I knew that fraternal twins could run in a family - but that it has to come through the mother and I knew that identical twins are a always just flukes. Other than that - I didn't know a thing. Oh, I knew that identical twin pregnancies could be riskier than fraternal ones.

Since then I have learned quite a lot and I've decided to share my new knowledge with you all (lucky you! ;)

*Fraternal twins happen when two eggs get fertilized. They are as different from each other as two babies would have been from two separate pregnancies.

* Identical twins happen when a fertilized eggs splits into two growing organisms. Depending on when the split happens four things can happen:
- earliest split - both babies end up with their own complete environment from amniotic sac, placentas, chorions, everything. This pregnancy would look pretty much the same as a fraternal twins pregnancy
- medium split (most common) - both babies have their own sacs, but they end up with some shared stuff (ie placenta, chorion)
- later split (and the least common) - both babies end up in one amniotic sac. This is very dangerous because they can ended up twisting themselves (and their umbilical cords) all up and it can cause a lot of problems.
- latest split - Siamese twins. They split so late they didn't completely split.

So what does this mean? It means that the only way to know for sure what kind of twins you have are if you have twins that share a placenta, chorion or amniotic sac (automatically identical) or if, later on, you find out that the babies aren't of the same gender (automatically fraternal). It is possible that you could go your entire pregnancy and not know if the twins are identical or fraternal if they are the same gender. And when they are born, if they look really similar, you might even have to have dna testing to determine which kind they are (there are, after all, some very similar looking non-identical twins out there. For example the Olsen twins!)

At my latest doctor's appointment the ultrasound report the doctor had had an analysis on it from a specialist other than the technician who shared the twin news with us. It said that the twins are likely fraternal. There was no more information than that. Given what I've learned (and my research is not scientific here - it's pretty much wikipedia ;) I THINK that means that the twins have their own everything (which is very good!) and that *most* identical twins end up sharing something. Therefore, it is most likely that mine are fraternal but it's not written in stone. I am, amazingly, not really obsessing on it (I thought I would to be honest) and am instead ready to wait and find out. I am very curious on the gender of these babies though, mostly because I want to see if the remainder of my whole "prediction" comes through and that they end up both being girls. My next ultrasound is January 5 so we have a ways to go yet. Hopefully they'll both cooperate and show us the goods ;)

Oh. And I also found out this week that my mother's cousin had fraternal twins. So I guess it does run in the family... ;)

7 comments:

Lindsay said...

So this is what you did instead of coming over and eating pizza and cake/contracting my childrens' various diseases?

Lida said...

There are twins on Eric's side as well. His great uncle and aunt on his Mom's side have twins (um,first cousins once removed?) but since it's supposed to come from the Mom's side that doesn't count right?

crazy working mom said...

We had twins in both sides of our family. Really, I am glad we didn't have any multiple births. Best of luck to you.

Anonymous said...

Yeah, but don't all babies look alike when they're born anyways? ;o)

Some kind of Wondermom said...

I hope it's two girls!!! OMG I'm going to have so much fun shopping for them! :)

Jay said...

It seems like sweet happiness either way.

Sarah, Goon Squad Sarah said...

As a bonus, if you do have same sex twins that each have their own placenta/sacs etc. the only way to tell for sure if they are identical or not is with a (very expensive) blood test.

MOst people these days don't even do the test. They just guess or say they don't care.

(Thank you twins club for my extensive knowledge on same sex twins - mine are b/g)