PSA: Identical vs fraternal ultrasound pics

pea-kay · February 2010

This comes up a lot, so here are some graphics I came up with to help explain. (And I'm truly not being snarky - this is something I learned after I went through my own pregnancy, not ever being told that my boys were monochorionic, and wondering even after they were born if they were identical.)

in the second picture I say (probably) because 1 in 9 dichorionic twins are actually monozygotic, meaning the egg split early enough that two chorions formed.

Here are some real examples of early ultrasounds:

Monochorionic (look at top picture)
Monochorionic
Monochorionic

Dichorionic
Dichorionic

Hope that helps!

BitterOldHag · February 2010

The last one looked exactly like mine. The u/s tech said they had 'bunk beds'!

Temp159135562506975 · February 2010

omg- pam- you make me laugh.

my boys had the same smiles at 8 weeks, too! lol

babya2010 · February 2010

Ha, this is so funny! My ultrasound pic looked like the 2nd one and yep - fraternal

RoseWhite · February 2010

My U/S pic looked like the second one...and identical!

Their smiles were just like your picture though

amanda31H · February 2010

Peakay--

Thanks! I still find this all confusing!

My early u/s didn't look like any of the ones shown---- I was also getting one b/c I was spotting, thought I was miscarrying, but low and behold they told me I had twins and a low lying placenta! Anyway...all of that said, it was an emotional time and I asked VERY few questions! My first u/s was transvaginal, they said there were two placentas, and that there was a thin membrane in between. That was at 13 weeks.

I had an u/s at18 weeks- not transvaginal. The MFM who reviewed it said there was only 1 placenta (the transvaginal was done at a different location and he said they probably couldn't get as good a look with that type), I know they are each in their own amniotic sac, with a thin membrane in between.

I've been told my girls are very likely identical and are monochorionic diamniotic. The MFM said since they were sharing a placenta, and were separated by a thin membrane, those were all indicators of ID twins - he was 90% sure.

I just read something recently about "gestational sac". Is that the membrane they are referring to? Or is that the same thing as amniotic sac?

Are my girls monozygotic? Everytime I think I understand... I start to question everything!

Shannonlea · February 2010

I always love those graphics

CrazeyJaneyR · February 2010

I love this illustration!

?

Mine looked like the top, but with a very thin membrane btw the 2. I was told identical, but now I suspect differently.?

BizEB · February 2010

Cute

For those with di di twins (like me) wondering if they are the 1 in 9 with identicals, my MFM told me that another strong indicator that the twins are fraternal is a "twin peak", a little triangle, between the two sacs.

CrazeyJaneyR · February 2010

BizEB:
Cute
For those with di di twins (like me) wondering if they are the 1 in 9 with identicals, my MFM told me that another strong indicator that the twins are fraternal is a "twin peak", a little triangle, between the two sacs. ?

?

oh!! Do you have an example??

pea-kay · February 2010

BizEB:
Cute
For those with di di twins (like me) wondering if they are the 1 in 9 with identicals, my MFM told me that another strong indicator that the twins are fraternal is a "twin peak", a little triangle, between the two sacs.

here's a PDF with a picture of what this looks like.

pea-kay · February 2010

And this isn't a bad website to check out, it has more pics.

https://soyourepregnantwithtwins.blogspot.com

pea-kay · February 2010

amanda31H:
Peakay--

Thanks! I still find this all confusing!

My early u/s didn't look like any of the ones shown---- I was also getting one b/c I was spotting, thought I was miscarrying, but low and behold they told me I had twins and a low lying placenta! Anyway...all of that said, it was an emotional time and I asked VERY few questions! My first u/s was transvaginal, they said there were two placentas, and that there was a thin membrane in between. That was at 13 weeks.

I had an u/s at18 weeks- not transvaginal. The MFM who reviewed it said there was only 1 placenta (the transvaginal was done at a different location and he said they probably couldn't get as good a look with that type), I know they are each in their own amniotic sac, with a thin membrane in between.

I've been told my girls are very likely identical and are monochorionic diamniotic. The MFM said since they were sharing a placenta, and were separated by a thin membrane, those were all indicators of ID twins - he was 90% sure.

I just read something recently about "gestational sac". Is that the membrane they are referring to? Or is that the same thing as amniotic sac?

Are my girls monozygotic? Everytime I think I understand... I start to question everything!

I wonder if yours are the kind like RoseWhite has - di/di identicals. Maybe the egg split early but the sacs implanted close to each other? hmmm. Interesting...

FYI - gestational sac is the large outer sac, the amniotic sac is the inner sac around each baby, and that's the membrane they're referring to. in my handy-dandy illustrations, the black circle that the babies are in is the gestational sac.

JustaKidAtHeart · February 2010

my u/s with a twin peak

amanda31H · February 2010

pea-kay:
amanda31H:

Peakay--

Thanks! I still find this all confusing!

My early u/s didn't look like any of the ones shown---- I was also getting one b/c I was spotting, thought I was miscarrying, but low and behold they told me I had twins and a low lying placenta! Anyway...all of that said, it was an emotional time and I asked VERY few questions! My first u/s was transvaginal, they said there were two placentas, and that there was a thin membrane in between. That was at 13 weeks.

I had an u/s at18 weeks- not transvaginal. The MFM who reviewed it said there was only 1 placenta (the transvaginal was done at a different location and he said they probably couldn't get as good a look with that type), I know they are each in their own amniotic sac, with a thin membrane in between.

I've been told my girls are very likely identical and are monochorionic diamniotic. The MFM said since they were sharing a placenta, and were separated by a thin membrane, those were all indicators of ID twins - he was 90% sure.

I just read something recently about "gestational sac". Is that the membrane they are referring to? Or is that the same thing as amniotic sac?

Are my girls monozygotic? Everytime I think I understand... I start to question everything!

I wonder if yours are the kind like RoseWhite has - di/di identicals. Maybe the egg split early but the sacs implanted close to each other? hmmm. Interesting...

FYI - gestational sac is the large outer sac, the amniotic sac is the inner sac around each baby, and that's the membrane they're referring to. in my handy-dandy illustrations, the black circle that the babies are in is the gestational sac.

Yes, from what they told me, and from what I've read, if the egg splits early you get two amniotic sacs, but can still get one placenta. Ok... I get what the membrane is now... I always assumed they were referring to the gestational sac. Hmm, lots more to ask now when I go back!

macchiatto · February 2010

You're the bomb diggety, peakay.

pea-kay · February 2010

amanda31H:
Yes, from what they told me, and from what I've read, if the egg splits early you get two amniotic sacs, but can still get one placenta. Ok... I get what the membrane is now... I always assumed they were referring to the gestational sac. Hmm, lots more to ask now when I go back!

And if it splits even earlier than that, you get two placentas and your u/s would look like my "fraternal" pic above. which is why it says "probably" because most of the time, those twins are fraternal. but not always (see RoseWhite.)

SMILEYD · February 2010

SO interesting! Thanks! my 8wk sono looks like the 1st one and I was told most likely identical. I also had her ck last week and she said even though they are in the same sac, they each have a placenta.

Does that make sense?

amanda31H · February 2010

pea-kay:
amanda31H:

Yes, from what they told me, and from what I've read, if the egg splits early you get two amniotic sacs, but can still get one placenta. Ok... I get what the membrane is now... I always assumed they were referring to the gestational sac. Hmm, lots more to ask now when I go back!

And if it splits even earlier than that, you get two placentas and your u/s would look like my "fraternal" pic above. which is why it says "probably" because most of the time, those twins are fraternal. but not always (see RoseWhite.)

Yep, that's what they said. I also read in a couple of places that two placentas can fuse together--- but from what I read and what the doctor said that would happen later on. I thought maybe that's why the first u/s tech and doctor said there were 2, and then 5 weeks later there was 1!

The MFM was funny... he said he's 90% sure they are ID... but to just wait a few months and see if they really look alike and not bother paying for the test!

amhalp1 · March 2014

Here are my first twin ultrasound pics. We went through IVF and implanted two healthy embryos that both took and will end up in our fraternal twins

I'm at 9 weeks now with another ultrasound tomorrow...wish me luck!

amhalp1 · March 2014

Sorry, forgot to attach...

TheDairyQueenx3 · March 2014

Another zombie thread! It's the apocalypse around here

3rd time this week. This thread is as old as my preschooler.

ceechie · March 2014

Ahhhh! I didn't even look at the dates!
So much edumaction in one thread...,

pea-kay · March 2014

I updated all the pictures and added some more here:

Types of Twins and Triplets

TheDairyQueenx3 · March 2014

The little babies make me laugh. It's the smiley faces on them!

macchiatto · March 2014

TheDairyQueenx3 said:

Another zombie thread! It's the apocalypse around here 3rd time this week. This thread is as old as my preschooler.

LOL
It is a great thread though!
And Peakay, I had forgotten you weren't told during pregnancy that your boys were monochorionic. That's crazy.

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