diamniotic/dichorionic=2 sacs, 2 placentas - usually fraternal, but identical in rare cases when egg splits very early.
diamniotic/monochorinic=2 sacs one placenta=identical
mononamnioic/monochorionic=one sac one placenta =identical
In the lab report for my first ultrasound at 8 weeks, they said they were di/di, so my doc said fraternal.
IN the one yesterday, I asked the us doc if he could tell before delivery without revealing gender, and he said no, and that he couldn't tell if they were id or fraternal.
am I missing something? Do they examine the placentas at birth, or do dna tests? Is it only possible to tell for sure if they share a sac or if genders are opposite?
TIA/:goodvibes:
Outnumbered
03-27-2009, 10:47 AM
I was told that we could only tell by doing a DNA test. Our genetic counselor told us that about 30% of same sex di/di twins are identical. Honestly, it's just not that important to me and I'm not forking out $300 for a DNA test. And you'll find that most medpros don't know much about twinning. I can't tell you how many docs/nurses assumed that my boys are fraternal based only on the fact that there were 2 placentas.
laj
03-27-2009, 03:16 PM
And the DNA tests can also come back inconclusive, so that's not even a sure way of finding out. Our guys were di/mo so we assumed identicals (and the fact that we did IVF and only had one embie to transfer), but they sure don't look identical. Congrats and good luck!
HeatherlovesCDs
03-27-2009, 07:36 PM
Yes, they can be di/di and still be id twins. If the egg splits early enough, even id twins will be completely separate in terms of placenta and all. And, on top of that, even if you have same gender twins and it appears they only have one placenta, it can still be frats. The 2 placentas can fuse and appear to be one. If they are for sure in the same sac, then they are definitely ID. But, it's very hard to tell for sure. I know several twin moms that were told they were in the same sac when in fact they were not. One of which had triplets and was told 2 of them were ID because they were in the same sac. Well, not only were they not in the same sac, but they are in fact frats. (It's totally obvious. There is no way they are ID. No DNA test needed.) So, until they are born, you can't know. After birth, they can see for sure it they were in the same sac and they can have the 1 placenta analyzed to see it was in fact only 1 or 2 fused. So, if they are found to be in the same sac or only one placenta then no DNA is needed. They are definitely ID. But, on the other hand, if it's proven there was 2 of everything and they are same gender and they look alike, you still won't know unless you get DNA. I personally would definitely do it. It would drive me crazy not to know. That's just me though. I don't have to worry about it as mine are B/G. I hope that all made sense. Good luck with the mystery.
mammaof??
03-28-2009, 11:51 AM
Yes, they can be di/di and still be id twins. If the egg splits early enough, even id twins will be completely separate in terms of placenta and all. And, on top of that, even if you have same gender twins and it appears they only have one placenta, it can still be frats. The 2 placentas can fuse and appear to be one. If they are for sure in the same sac, then they are definitely ID. But, it's very hard to tell for sure. I know several twin moms that were told they were in the same sac when in fact they were not. One of which had triplets and was told 2 of them were ID because they were in the same sac. Well, not only were they not in the same sac, but they are in fact frats. (It's totally obvious. There is no way they are ID. No DNA test needed.) So, until they are born, you can't know. After birth, they can see for sure it they were in the same sac and they can have the 1 placenta analyzed to see it was in fact only 1 or 2 fused. So, if they are found to be in the same sac or only one placenta then no DNA is needed. They are definitely ID. But, on the other hand, if it's proven there was 2 of everything and they are same gender and they look alike, you still won't know unless you get DNA. I personally would definitely do it. It would drive me crazy not to know. That's just me though. I don't have to worry about it as mine are B/G. I hope that all made sense. Good luck with the mystery.
totally agree with heather. mine are both b/g and there were definitely two sacs and two placentas- although with the first set, they did fuse together, you could still clearly see the line between them. everyone i know with same sex twins has had them tested and i would say that 90% are ID. for me, it would be good to know b/c fraternal twins are genetic and identical twins are not. and there's all that cool ID twin stuff- more shared personality/physical traits/sensitivities, etc...
justjess
03-28-2009, 11:59 AM
oh how exciting! twins are super fun! dont know about all that identical stuff but know i have a friend who was told her boys werent id and wow did they ever look like they were for about the first 5 years of their life. even now i still have a little trouble telling them apart but they have changed a bit so as not to be really truly id! hope you figure it out if it matters. best of luck on the rest of your pregnancy and delivery!
Kita
03-28-2009, 12:10 PM
I agree with the PPs. And, it might be obvious once babies are born what you have. I have fraternal boys, and they looked a lot different (to me) right from birth.
Rollins4
03-28-2009, 02:23 PM
We were told the boys were mono/mono,, then at our last peri appt,, they found a very thin line that they thought then could be two sacs, but only one placenta was seen,, fast forward,, C-section, 2 placentas, 2 sacs. And when the boys were born, they look like siblings and our older kids but for sure not identical,, we were curious and our insurance covered it, so DNA determined they were fraternal not identical!
i&a's mama
03-28-2009, 05:20 PM
Like the other mamas said, a DNA test is the only way to tell, unless they can see that they share a sac on the u/s. But even that's not exact, as in the case of the pp! Placentas do fuse, so that doesn't tell. You'll just have to wait and see, and decide if you want the test. :goodvibes:
The good news is, they have their own rooms. :giggle: People love the novelty of id twins, but really, it's best if they have their own room and own food.
kristinc
03-28-2009, 07:11 PM
one of our sets of twins is dizygotic/diamniotic but is identical twins....it is rare but does happen. they only way we know this is true is that we only transferred 3 embryos and have 4 babies, but every U/S the tech and the doctor agree that they all have their own sacs & placentas.
after birth the pathologist examines the placenta to see if they can tell what the babies are....gender & blood type can help in identifying but dna is the definitive:-)
Jeb-O
03-28-2009, 10:21 PM
There is an online DNA test that is $99. That is the only "true" way to know.
I'm 99% certain ours are frats, but they were never tested. They just look like total opposites, were in separate sacs and had fused placentas.
mommygonewild
03-29-2009, 05:51 PM
my guys had separate sacs and they said they could not tell if they were diamniotic/monochorinic util after birth.
as far as i know monochorionic doesn't necessarily mean they share the same placenta, but the outer chorion/outer membrane that surrounds the sacs.
here's what I just found on About.com
When monozygotic twins are contained in a shared chorion, they are referred to as monochorionic. The chorion is the outer membrane of the sac surrounding a fetus in utero. Monochorionic twins can be either monoamnionic or diamnionic.
so basically they couldn't tell if one egg split or not. the only sure way to tell in utero would be if they shared a sac...mo/mo.
so after my guys were born they examined and determined they did share the outer chorion and are identical.
hope this helps. i know you get conflicting info.
#1 Rule - Do not listen to the US tech, they are NOT doctors (unless it's your Dr reading it).
Twinvillageiowa
03-29-2009, 11:01 PM
You actually can't tell without a blood test for di/di. That is what mine are and we were told that 100% they were frat. but nope, they are ID!!!! We did a cheek swab test when they were about 1 and just like I kept saying, they are identical. Having seperate everything just means that the egg split really early :thumbsup:
Twinvillageiowa
03-29-2009, 11:04 PM
And FWIW, I would do the dna test. It is only like $100 bucks and ID twins are direct organ donors and blood donors.
GirlyMama81
04-01-2009, 03:37 PM
We were also told the only true way to tell is by DNA. My twins each had their own sac and placenta and they are identical. We did do DNA but it only cost like $120 from a lab I found an add for in a twin magazine. Mine are greater than 99% identical. But if I had waited I would of known. They will be 6 on Halloween and if they are seperate I have even mixed them up. Bad mommie!!
TwinKristi
04-01-2009, 06:46 PM
We were also told the only true way to tell is by DNA. My twins each had their own sac and placenta and they are identical. We did do DNA but it only cost like $120 from a lab I found an add for in a twin magazine. Mine are greater than 99% identical. But if I had waited I would of known. They will be 6 on Halloween and if they are seperate I have even mixed them up. Bad mommie!!
My twins were later determined to be identical after my entire pregnancy I was told they were fraternal b/c they had seperate sacs. BUT at birth we were told there was an 80% chance they were frat. and only 20% that they were identical due to one placenta but whether or not it was fused was the question. I never heard anything back from pathology about it. I asked our Ped what she thought just looking at them and she said identical because they both had ingrown toenails on one foot pretty bad and the other foot just a little. LOL
It was never really a big deal, they don't really look alike to me, but to everyone else they do. :giggle: Some people can't even tell them apart. But we participated in an MIT Twin Language Research Study when they were about 1 or 2yrs old and got t-shirts and $20 every month plus at the end you got free zygosity testing. 3 YEARS LATER no to mention 2 or 3 houses later... I get a postcard in the mail offering us our DNA testing since we were on file as never recving it! I was so excited and they sent us the kit and we sent it back and within a couple weeks we found out they were 99.999999998% identical!! LOL It was a fun experience since EVERYONE asks, but I never would have paid for it OOP. :blush:
And I don't know if anyone has mentioned this as I only scanned the posts, but there are actually rare forms of identical b/g twins and idendtical mirror twins as well as twins who have been conceived from 2 sperm inside one sac of 2 eggs... it's crazy! I watched a show on Discovery Health on twins recently and they talked a LOT about the different types.
HeatherlovesCDs
04-01-2009, 07:59 PM
And I don't know if anyone has mentioned this as I only scanned the posts, but there are actually rare forms of identical b/g twins and idendtical mirror twins as well as twins who have been conceived from 2 sperm inside one sac of 2 eggs... it's crazy! I watched a show on Discovery Health on twins recently and they talked a LOT about the different types.
I saw that too! It's crazy all the different things than can happen. The b/g id's are so rare, I never bring it up. I think that's what happens when the 2 sperm fertilize one egg or something like that, but I can't remember. Oh wait! I remember. It's when the sperm that fertilizes the egg has an extra x gene. So instead of being xy or xx, its xxy. This is actually a condition that can happen to a singleton boy. I can't remember what it's called or what it's symptoms are. Anyway, it when the egg splits, one becomes xx and the other xy (boy/girl). I knew some twins in high school that were g/b that I would have thought were ID if I didn't know better. Anyway, mine are g/b and when people ask I do tend to say something like, "well, they are g/b so not id." But, in the back of my mind I think of that show and the rare chance that it does happen. It's like 1 in a million or something though.
