what kind of twins do I have?

diego299

Has been my question since 5 wks 3 days when we saw what we thought were two sacs. There are two babies that appear to be in two different sacs. My OB says she can't tell if they are identical or fraternal. We've had 6 u/s shouldn't we know by now? I know some cases you won't know unless bw is done after delivery but that's rare right?

Mrs.AshAsh

Im no expert by any means but from my understanding, identicals can be in a sac and have a thin membrane that seperates them. When I found out I am pregnant with twins we were able to see 2 sacs, 2 placentas and the tech was able to see that I ovulated twice from the right side so its likely my twins are fraternal. But there is still a chance that one egg didnt develop and the other split, although its not likely.

aliwisewoman

Here is the breakdown. Out of all twins, fraternal and identical, 30% are identical and 70% are fraternal.

Fraternal twins are di/di (dichorionic/diamniotic). Every now and then, the two placentas implant close together and the placentas will fuse, to look like one.

Out of all identicals, 30% will be di/di, the majority will be mo/di (monochorionic/diamniotic, meaning sharing a placenta with separate amniotic sacs), and a smaller percentage will be mo/mo (sharing a placenta and amniotic sac, this type of twins carries the most risk), and an even smaller percentage will be conjoined.  

So, in theory, if you have di/di twins there is a 90% chance they are fraternal and a 10% chance they are identical. Unless your di/di twins are boy/girl, have different blood types, or look completely different, the only way to know for sure is to have blood work done. 

pea-kay

More than likely fraternal, but possibly identical.

See here:

https://pyjammy.com/types-of-twinstriplets/

PurpleIris30

At 5w3d, seeing two sacs means two gestational sacs -- or what looks like two black blobs on the ultrasound screen.  The term "sac" gets confusing because it can also refer to amniotic sacs later in pregnancy (for instance, if you have one gestational sac -- or black blob on the screen -- you can still have two separate amniotic sacs within that.  Two amniotic sacs with one gestational sac or placenta means mo-di twins.)

In short, based on your description, it sounds like you are having di-di twins, and as a previous poster explained, your OB is correct that it is impossible to know if di-di twins are identical or fraternal.  Most are fraternal, but you can't say for sure prior to delivery, unless they end up being separate sexes.

diego299

Thanks everyone! I figured they were fraternal. I've been feeling a little iffy about my OB and decided to air a little of it here.

macchiatto

Yeah, my twins were di/di and we found out they were both boys so we decided after birth if they couldn't tell, we would get DNA testing done. (They are 4 and I still don't know their blood types but if their blood types are different, you know they're fraternal.) As it turned out, from day 1 we could tell they were fraternal so we never had them tested. Even though others would ask, "How can you tell them apart?!" till they were 9m or so, they have always had different hair color, different eyes, noses, chins, etc.

katiebenes

aliwisewoman:

Here is the breakdown. Out of all twins, fraternal and identical, 30% are identical and 70% are fraternal.

Fraternal twins are di/di (dichorionic/diamniotic). Every now and then, the two placentas implant close together and the placentas will fuse, to look like one.

Out of all identicals, 30% will be di/di, the majority will be mo/di (monochorionic/diamniotic, meaning sharing a placenta with separate amniotic sacs), and a smaller percentage will be mo/mo (sharing a placenta and amniotic sac, this type of twins carries the most risk), and an even smaller percentage will be conjoined.  

So, in theory, if you have di/di twins there is a 90% chance they are fraternal and a 10% chance they are identical. Unless your di/di twins are boy/girl, have different blood types, or look completely different, the only way to know for sure is to have blood work done. 

This. We haven't done tests on ours to be sure they are fraternal, but we know they *probably* are.
Though, if you're like me... you'll get sick of telling people that there is a chance that they are ID twins lol.

Now I basically smile and nod my head if someone assumes either way, unless its someone I talk to regularly. 

katiebenes

diego299:

Thanks everyone! I figured they were fraternal. I've been feeling a little iffy about my OB and decided to air a little of it here.

if your OB can't tell you mo/mo mo/di or di/di then I'd be iffy too lol.  

macchiatto

katiebenes:

diego299:

Thanks everyone! I figured they were fraternal. I've been feeling a little iffy about my OB and decided to air a little of it here.

if your OB can't tell you mo/mo mo/di or di/di then I'd be iffy too lol.  

Oh and yeah, I meant to ask why you're iffy on your doc. Definitely look for someone with a lot of multiples experience.

Lisa+K!

It might depend on the us machine. I am having id twins, but my doc wouldn't say for sure until 15 week visit. She said at the 11 week and the 15 week visit that if she couldn't see the dividing membrane I would have to go into the bigger city about an hour away to get a better view on the better machine. We did see a dividing membrane at 11 weeks and at 15 she said she could tell they were id by looking at the placenta based on the quality of the image. I hope this is helpful. I am still learning myself, but this is what I was told. Good luck :