Fraternal or Identical?

Hi everyone, I'm happy I found this site. I'm 25 with a 5 year old son and a 3 year old daughter. I am now 13 weeks pregnant with twins.

My first sonogram was at 10 weeks, this is when I found I was carrying twins. I was surprised to see two babies, but only because it confirmed my feelings. I had a gut feeling I was carrying twins because of some of my early symptoms, but that's another story. (I have a blog explaining this if anyone is interested in reading it: http://pregnancymigrainesandbabies.blogspot.com/)

I had my second sonogram the other day and the babies measured 12 weeks, 3 days and 12 weeks 4 days, right on target I'm told. My question is whether I'm carrying fraternal or identical twins. My doctor or sonographer either one mentioned anything about this.
This is what I know from my sonograms...I have two babies, two sacs, one placenta, and a very whispy membrane separates the babies, and the babies appear to be very close to one another. The very thin whispy membrane can be seen at times, but not at other times, and only pieces of it, not a full line between the two babies. Also, I've read about the "twin peak" and I didn't notice this during either sonogram. I also understand about the fusing of two placentas. So, I'm guessing in my case they can still either be fraternal or identical. But, I'm leaning more toward identical for some reason. The sonographer said he could probably see the genders, but he wouldn't tell us for fear he might be wrong; we have to wait until our next sonogram. I'm not scheduled for my next sonogram until I'm 19 weeks (about 6 more weeks), but I do have another doctor appointment in 4 weeks, which I've heard he will probably do a quick sonogram in the office at that time. But, if the babies are sharing a placenta, should I be waiting that long before my next sonogram? The babies are growing approximately at the same rate so far.

 

If you indeed have only one placenta, then they are identical. The placenta can be fused, though, but it's early for that, and can also be early to tell for sure the chorionicity (whether you have 1 or 2 placentas). However, the thin membrane can be indicative of one placenta and your u/s techs and doctors would be the ones to confirm the chorionicity.

One placenta means monochorionic, two placentas is dichorionic. One amniotic sac is monoamniotic and likewise, two amniotic sacs is diamniotic. So if you have one placenta and two amniotic sacs, the twins are categorized as monochorionic/diamniotic or shorted to either mono/di or mo/di here on the boards.

Monochorionic means that the babies are identical. Dichorionic can mean identical or fraternal, but is more likely fraternal than identical. If there are 2 placentas, the only real ways to tell if the babies are identical would be to wait until after birth and first check blood types, if the blood types are the same then they could still be identical so you wait to see what they look like. They can still look alike and be fraternal or look a little different and still be identical, so if they don't look entirely different, then a DNA test is the most conclusive way to tell.

Congratulations on your twin pregnancy! :hug99:

 

It sounds very likely that you are carrying ID's .. but its real tough to be sure, although if they ARE sharing a placenta then they def are. Placentas CAN fuse .. but you are really early on your pregnancy so to me it seems unlikely that there were 2. I know I had to go through the guessing game for most of my pregnancy .. but I didnt even find out I was having twins until I was like 21 weeks along .. you're fortunate to know so early.

Good luck and keep us updated !

 

QUOTE(Lizzybo @ Aug 10 2008, 03:55 PM) [snapback]923300[/snapback]
If you indeed have only one placenta, then they are identical. The placenta can be fused, though, but it's early for that, and can also be early to tell for sure the chorionicity (whether you have 1 or 2 placentas). However, the thin membrane can be indicative of one placenta and your u/s techs and doctors would be the ones to confirm the chorionicity.

One placenta means monochorionic, two placentas is dichorionic. One amniotic sac is monoamniotic and likewise, two amniotic sacs is diamniotic. So if you have one placenta and two amniotic sacs, the twins are categorized as monochorionic/diamniotic or shorted to either mono/di or mo/di here on the boards.

Monochorionic means that the babies are identical. Dichorionic can mean identical or fraternal, but is more likely fraternal than identical. If there are 2 placentas, the only real ways to tell if the babies are identical would be to wait until after birth and first check blood types, if the blood types are the same then they could still be identical so you wait to see what they look like. They can still look alike and be fraternal or look a little different and still be identical, so if they don't look entirely different, then a DNA test is the most conclusive way to tell.

Congratulations on your twin pregnancy! :hug99:



Thank you for the congrats. We are excited about having twins. I realize they will be a challenge. Sometimes with my 3 and 4 year old they feel like I have twins already (they're 17 months apart).
I'm understanding all of what you are saying about monochorionic and dichorionic. I just wonder why the sonographer or the doctor either one even mentioned anything about identical or fraternal. Maybe after the next sonogram we may know what their genders are thus possibly eliminating them being identical (if they are boy/girl twins).

Thanks so much again for the information.

 

QUOTE(Moodyzblu @ Aug 10 2008, 03:56 PM) [snapback]923301[/snapback]
It sounds very likely that you are carrying ID's .. but its real tough to be sure, although if they ARE sharing a placenta then they def are. Placentas CAN fuse .. but you are really early on your pregnancy so to me it seems unlikely that there were 2. I know I had to go through the guessing game for most of my pregnancy .. but I didnt even find out I was having twins until I was like 21 weeks along .. you're fortunate to know so early.

Good luck and keep us updated !



Thank you so much. I know I hate the guessing and waiting game. Isn't it funny how our pregnancies seem to take forever, but once the babies get here, they seem to grow so fast...time flies!

I wasn't told at my first sonogram about having one placenta, she was only looking for two yolks. Which she found one, it was as clear as can be, but once she found the second one, it was very faint looking. Even back then, the membrane separating the two was still whispy and not seen very easily.

I wonder how early two placentas fuse together. I'm still leaning toward identical twins, but I was hoping for a boy/girl combo.

Thanks again. I'm happy I found this site, there is so much useful information here, I will be visiting very often.

 

My first sono at 11 weeks the dr. said she eiother saw one placenta or fused and 2 sacs so it could have been ID or frat. She continued to say that at my next two appt's. Then at my peri appt she did another sono and is better at reading them I assume and they were clearer, and she saw 2 totally separate placentas on the opposite sides of my babies sacs, so they could never have been fused. She missed one obviously. My official 20 wk sono confirmed this last week and I am having a boy and a girl. Early on its hard to tell.

 

QUOTE(jordynsmama+2 @ Aug 10 2008, 06:26 PM) [snapback]923462[/snapback]
My first sono at 11 weeks the dr. said she eiother saw one placenta or fused and 2 sacs so it could have been ID or frat. She continued to say that at my next two appt's. Then at my peri appt she did another sono and is better at reading them I assume and they were clearer, and she saw 2 totally separate placentas on the opposite sides of my babies sacs, so they could never have been fused. She missed one obviously. My official 20 wk sono confirmed this last week and I am having a boy and a girl. Early on its hard to tell.


Thank you for sharing with me. There was no mention of a placenta at all with my first sonogram at 10 weeks. Then my second sonogram was at 12 and 1/2 weeks and the sonographer said he could only see one placenta.

My next sonogram isn't until I'm 19 weeks, but I see my doctor in about 3 weeks (I'll be just over 16 weeks) and I'm assuming he will do a sonogram at that time also.

I guess I wouldn't have to wonder about all this if I knew they are boy/girl twins.

Congratulations on your twins.

 

QUOTE(Soon to be Mom of 4 @ Aug 10 2008, 08:39 PM) [snapback]923485[/snapback]
Thank you for sharing with me. There was no mention of a placenta at all with my first sonogram at 10 weeks. Then my second sonogram was at 12 and 1/2 weeks and the sonographer said he could only see one placenta.

My next sonogram isn't until I'm 19 weeks, but I see my doctor in about 3 weeks (I'll be just over 16 weeks) and I'm assuming he will do a sonogram at that time also.

I guess I wouldn't have to wonder about all this if I knew they are boy/girl twins.

Congratulations on your twins.

Yeah see at that time the dr. could have only seen one or whatever. My dr. kept saying she saw one or fused at my 11 wk, 14 wk and 17 wk.....my peri appt with a better dr. was at 19 wks and she is the one who saw both placentas, as well as the u/s tech last week. I wondered all the way to 19 wks whether they were ID or frat just like you and thought, "ugh, I wont know unless its a boy/girl." But when she saw 2 placentas nat the peri appt and she saw that one baby was a boy, she said they were most likely fraternal and that the other baby could be either. Then I found out from the u/s tech the other twin was a girl. So yours is still a toss up I would say-
Also my membrane was very noticible at the 11 wks-I am going to post a pic of that picture b/c its pretty cool and very clear of both babies and the sacs. I will post it tomorrow.

 

They couldn't see my placenta easily and they didn't see it until 15 weeks, though I had several ultrasounds before that. They only saw one mass of placenta so they said they were 80% sure they are dichorionic based on the membrane thickness and on the direction of the umbilical cords.

A lot of doctors and techs are only interested in the chorionicity due to risks. It is higher risk to have monochorionic twins and thus, the pregnancy needs more monitoring. They seem only interested in whether the babies are frat or id from a clinical perspective. We also wanted to learn the genders asap because one of our doctors suspected TTTS, and ours are both boys, so it doesn't rule out ID, but it is the membrane thickness that makes our docs now think that they are dichorionic.

When is your next u/s?

 

QUOTE(jordynsmama+2 @ Aug 10 2008, 09:59 PM) [snapback]923714[/snapback]
Yeah see at that time the dr. could have only seen one or whatever. My dr. kept saying she saw one or fused at my 11 wk, 14 wk and 17 wk.....my peri appt with a better dr. was at 19 wks and she is the one who saw both placentas, as well as the u/s tech last week. I wondered all the way to 19 wks whether they were ID or frat just like you and thought, "ugh, I wont know unless its a boy/girl." But when she saw 2 placentas nat the peri appt and she saw that one baby was a boy, she said they were most likely fraternal and that the other baby could be either. Then I found out from the u/s tech the other twin was a girl. So yours is still a toss up I would say-
Also my membrane was very noticible at the 11 wks-I am going to post a pic of that picture b/c its pretty cool and very clear of both babies and the sacs. I will post it tomorrow.


My first sonogram, I could barely see the membrane, just a whispy thin line. The sonographer didn't mention placentas at all, she said she was just looking for two yolks.
My second sonogram, was the same, I could hardly see a membrane. I saw parts of a thin membrane, but never a full line. The sonographer said that he could only see one placenta.
I'll send a link to my last sonogram, check it out and see what you think. I look forward to seeing your sonogram.
No matter if they are fraternal or identical, it's a thrilling journey.

[[/img]

 

QUOTE(Lizzybo @ Aug 10 2008, 11:07 PM) [snapback]923732[/snapback]
They couldn't see my placenta easily and they didn't see it until 15 weeks, though I had several ultrasounds before that. They only saw one mass of placenta so they said they were 80% sure they are dichorionic based on the membrane thickness and on the direction of the umbilical cords.

A lot of doctors and techs are only interested in the chorionicity due to risks. It is higher risk to have monochorionic twins and thus, the pregnancy needs more monitoring. They seem only interested in whether the babies are frat or id from a clinical perspective. We also wanted to learn the genders asap because one of our doctors suspected TTTS, and ours are both boys, so it doesn't rule out ID, but it is the membrane thickness that makes our docs now think that they are dichorionic.

When is your next u/s?


That's interesting about the placenta. There has been no mention about the umblical cords yet. And no mention about fraternal or identical.
At my second ultrasound (12 and 1/2 weeks), the sonographer said he wasn't too concerned about only one placenta at this time. He said when I'm back for my 19 week one (the big one), they will be looking more indepth at every thing.

So, the size of the membrane gives them a clue as to being fraternal or identical? Do you have pictures of your sonogram you can post? I posted one of mine on another posting here (I think it's on the post just before this one), you can see there isn't much of the membrane showing. I hope you don't have to worry about TTTS, good luck to you.

My next ultrasound is scheduled September 24th, that's seven weeks after my second sonogram. It seems like they would have scheduled them closer than that. I do have a doctor appointment in 3 weeks, so I'm sure he will give me an ultrasound while I'm at that visit. It would be reassuring if he did.

 

If your twins truly share a placenta - they are ID.

Probably your best shot of telling if they are monochorionic is from one of your earlier scans, maybe your 10w scan - if there is one big black spot with two babies in it, they are monochorionic = 1 placenta = identical.

My 8w scan looked like this - one big black spot with two babies in it.
http://i2.photobucket.com/albums/y2/colofisch/us2.jpg

If they are dichorionic (2 placentas) there will be two big black spots with one baby in each.

If you saw a membrane, then they are diamniotic, anyway.

In short - if you have mo/di twins, you need to be monitored for TTTS. My TTTS was first found with a 20% size difference at 16 weeks, and then at 18 weeks, I saw a peri and one baby had NO fluid, and they were in trouble. I got seen weekly after that, was put on bedrest and watched very closely. With no signs of TTTS, you should still be monitored every other week, IMO. The things to ask about with your dr are:
fluid levels for each baby
cord doppler readings
visible bladders
signs of hydrops
size discrepancy

You should also go to the TTTS foundation website and ask there for help, plenty of people there will tell you the same thing!

Good luck - find a dr that will support you and answer your questions about TTTS. Many drs aren't that familiar with it, and it happens in more mo/di pregnancies than you think.

ETA: We didn't even SEE a membrane until 16 weeks!

 

QUOTE(ferfischer @ Aug 11 2008, 09:24 AM) [snapback]924335[/snapback]
If your twins truly share a placenta - they are ID.

Probably your best shot of telling if they are monochorionic is from one of your earlier scans, maybe your 10w scan - if there is one big black spot with two babies in it, they are monochorionic = 1 placenta = identical.

My 8w scan looked like this - one big black spot with two babies in it.
http://i2.photobucket.com/albums/y2/colofisch/us2.jpg

If they are dichorionic (2 placentas) there will be two big black spots with one baby in each.

If you saw a membrane, then they are diamniotic, anyway.

In short - if you have mo/di twins, you need to be monitored for TTTS. My TTTS was first found with a 20% size difference at 16 weeks, and then at 18 weeks, I saw a peri and one baby had NO fluid, and they were in trouble. I got seen weekly after that, was put on bedrest and watched very closely. With no signs of TTTS, you should still be monitored every other week, IMO. The things to ask about with your dr are:
fluid levels for each baby
cord doppler readings
visible bladders
signs of hydrops
size discrepancy

You should also go to the TTTS foundation website and ask there for help, plenty of people there will tell you the same thing!

Good luck - find a dr that will support you and answer your questions about TTTS. Many drs aren't that familiar with it, and it happens in more mo/di pregnancies than you think.

ETA: We didn't even SEE a membrane until 16 weeks!


Thank you for all the useful information, I appreciate it.
The sonographer nor the doctor seemed too concerned about just one placenta. They both said everything looked real good.
Here are pictures of my two sonograms.

The first one is at 10 weeks. I caught a glimps of a very thin whispy line between both babies, but it wasn't visible at all times.
The second one is at 12 and 1/2 weeks and it was the same thing with the whispy line.

(sorry the pictures aren't real clear, on the 10 week one, the tiny line is at the bottom between both babies)

http://i538.photobucket.com/albums/ff342/k...Ultrasound3.jpg

http://i538.photobucket.com/albums/ff342/k...ns8-06-08-2.jpg

Thanks again

 

those look monochorionic to me (but i'm no sonographer or anything).

also, i would say that you are ok on u/s frequency and monitoring until about 16-17 weeks, - that's when TTTS can make an appearance. So, I would try to take it easy until then. If you want to try to prevent TTTS (the jury is still out on this one) - take it easy - rest as much as you can (to maximize blood flow to the uterus - horizontal is better) and drink lots of water, eat plenty of calories and boost your protein intake. My TTTS stabilized with just bedrest and boosted protein intake, no amnios or surgery needed (yes, they CAN treat TTTS)! so we got very lucky!

Good luck - and congrats to you!

Don't worry too much about the membrane, the important thing is that there is one. When your drs measure the fluid level for each baby, they should find the membrane and measure the fluid on each side (since the pockets can "appear" to belong to one baby, but you're not really sure) For a while we didn't see a membrane because it was "shrink wrapped" around the baby with no fluid in her sac, so that's the other reason they'll look for it. But, every single u/s, every week, the membrane was really hard to find, but the found it so they could assess the fluid levels.

 

If I could figure out how to post a picture, I would show you my 11 wk. one. Mine are definitely di/di, and it looks a lot different than yours. Can you tell me how you got your picture on here?

 

QUOTE(Soon to be Mom of 4 @ Aug 11 2008, 01:09 AM) [snapback]923762[/snapback]
That's interesting about the placenta. There has been no mention about the umblical cords yet. And no mention about fraternal or identical.
At my second ultrasound (12 and 1/2 weeks), the sonographer said he wasn't too concerned about only one placenta at this time. He said when I'm back for my 19 week one (the big one), they will be looking more indepth at every thing.

So, the size of the membrane gives them a clue as to being fraternal or identical? Do you have pictures of your sonogram you can post? I posted one of mine on another posting here (I think it's on the post just before this one), you can see there isn't much of the membrane showing. I hope you don't have to worry about TTTS, good luck to you.

My next ultrasound is scheduled September 24th, that's seven weeks after my second sonogram. It seems like they would have scheduled them closer than that. I do have a doctor appointment in 3 weeks, so I'm sure he will give me an ultrasound while I'm at that visit. It would be reassuring if he did.


I'll try to find the 12 week sono pic for you and scan it but it won't be until tomorrow. We had fluid/sac size issues quite early, which was what made them suspect early onset TTTS. I boosted (with Boost) my protein intake and rested a lot more and eventually our twin-b got a nice healthy sac size. Since then things have looked really good. We now think that our issues were caused by protein deficiency, which made it tough for my body to properly process fluids, but the docs have so far pretty much ruled out TTTS (not 100% but close enough). I continue to be monitored every 3-4 weeks with u/s.

I agree that you should push for an ultrasound at 16 weeks. This is very important if you have a monochorionic pregnancy. If TTTS develops, there is a surgery that can help, and the earlier treatment is best.

 

QUOTE(ferfischer @ Aug 11 2008, 10:14 AM) [snapback]924493[/snapback]
those look monochorionic to me (but i'm no sonographer or anything).

also, i would say that you are ok on u/s frequency and monitoring until about 16-17 weeks, - that's when TTTS can make an appearance. So, I would try to take it easy until then. If you want to try to prevent TTTS (the jury is still out on this one) - take it easy - rest as much as you can (to maximize blood flow to the uterus - horizontal is better) and drink lots of water, eat plenty of calories and boost your protein intake. My TTTS stabilized with just bedrest and boosted protein intake, no amnios or surgery needed (yes, they CAN treat TTTS)! so we got very lucky!

Good luck - and congrats to you!

Don't worry too much about the membrane, the important thing is that there is one. When your drs measure the fluid level for each baby, they should find the membrane and measure the fluid on each side (since the pockets can "appear" to belong to one baby, but you're not really sure) For a while we didn't see a membrane because it was "shrink wrapped" around the baby with no fluid in her sac, so that's the other reason they'll look for it. But, every single u/s, every week, the membrane was really hard to find, but the found it so they could assess the fluid levels.


I think they look monochorionic too.
I've been drinking a lot of water and resting a whole lot! I think I eat a lot, I've already gained 16 pounds so far.
I'm happy things worked out for you, congratulations and your girls are beautiful.
I'll be sure to speak my concerns to the doctor when I see him again.
Thanks again.

 

QUOTE(azucena @ Aug 11 2008, 03:37 PM) [snapback]925116[/snapback]
If I could figure out how to post a picture, I would show you my 11 wk. one. Mine are definitely di/di, and it looks a lot different than yours. Can you tell me how you got your picture on here?


I think I accidentally loaded the picture the wrong way so it showed up in the post. I think it all depends on the link you put in your post.

Do you have photobucket? Or a place where you upload your pictures to? If not, most of them are free and they will give you the link codes.

When you go to post a comment:
1. Click where it shows a little picture, between the two green plus signs (insert image)
2. A small box will open where you will be able to insert a URL
3. Insert your URL and click ok (the html code should post the picture into your post, and the direct link will give a link to the picture in a separate window)
4. A link will show up in your post

If you need anymore help, let me know.
Congratulations to you! :drinks:

 

Reading all your replies, I would lean toward identical but it's still possible that they are fraternal. Studies looking at ultrasounds show that it is difficult to tell after 11 weeks if a placenta is actually a single placenta or two that are fused. Since your first u/s was at 10 weeks, you were close to the cut-off so I wouldn't say they are definitely identical but they certainly look that way.

Still, since there is the chance that you have a single placenta, you should be monitored for TTTS starting at around 17 weeks. The most important thing is to get ultrasounds at least every 2 weeks to watch for differences in amniotic fluid levels and size between the babies. Some doctors don't know much about TTTS so you may have to bring it to your doctor's attention. Don't let them brush you off, the monitoring has to be done. TTTS doesn't occur in 85-90% of monochorionic pregnancies but when it does happen it usually happens fast and needs to be treated quickly.

Congratulations on your twins!

 

here is a picture of my fraternal twins at 6 weeks in their separate sacs!!!!!!








http://s37.photobucket.com/albums/e61/ineedboobies/

 

QUOTE(Ali M @ Aug 11 2008, 09:21 PM) [snapback]925631[/snapback]
Reading all your replies, I would lean toward identical but it's still possible that they are fraternal. Studies looking at ultrasounds show that it is difficult to tell after 11 weeks if a placenta is actually a single placenta or two that are fused. Since your first u/s was at 10 weeks, you were close to the cut-off so I wouldn't say they are definitely identical but they certainly look that way.

Still, since there is the chance that you have a single placenta, you should be monitored for TTTS starting at around 17 weeks. The most important thing is to get ultrasounds at least every 2 weeks to watch for differences in amniotic fluid levels and size between the babies. Some doctors don't know much about TTTS so you may have to bring it to your doctor's attention. Don't let them brush you off, the monitoring has to be done. TTTS doesn't occur in 85-90% of monochorionic pregnancies but when it does happen it usually happens fast and needs to be treated quickly.

Congratulations on your twins!


I'll be sure to talk to the doctor about TTTS. They didn't seem to be too concerned about that yet. I have a doctor appointment in 3 weeks and I believe he will give me an ultrasound at that time. Then I have my "Big Ultrasound" at the end of September, I will be about 19 weeks.
Thanks for the information, it's very helpful.

Thanks for the congrats.
Congratulations on your little one on the way.

 

QUOTE(JESS6626 @ Aug 11 2008, 09:39 PM) [snapback]925649[/snapback]
here is a picture of my fraternal twins at 6 weeks in their separate sacs!!!!!!
http://s37.photobucket.com/albums/e61/ineedboobies/


Thanks for the picture. I see it looks like your babies have a large membrane between them. I didn't have my first sonogram until I was 10 weeks and I could hardly see the membrane at all. And then at 12 and 1/2 weeks, the membrane was still hard to see.
It will be interesting to see if the thin membrane could possibly mean they are identical. Time will tell I'm sure.

Congratulations to you on your twin pregnancy.

 

Yep. They are monochorionic. There is NO mistaking it when you see the one black spot w/ two babes in it!! (Like Ferifischer said) she is right. You are having ID's and this means you need to be seeing a Specialist starting NOW

You are now considered High Risk and should be monitored frequently for sure

CONGRATS and welcome to the wonderful world of ID's! You are going to LOVE IT!!!!

Make a Perinatologist Appt now

ENJOY!!

 

QUOTE(ivfbound078 @ Aug 12 2008, 07:26 AM) [snapback]926005[/snapback]
Yep. They are monochorionic. There is NO mistaking it when you see the one black spot w/ two babes in it!! (Like Ferifischer said) she is right. You are having ID's and this means you need to be seeing a Specialist starting NOW

You are now considered High Risk and should be monitored frequently for sure

CONGRATS and welcome to the wonderful world of ID's! You are going to LOVE IT!!!!

Make a Perinatologist Appt now

ENJOY!!


I think you're right about them being ID.
Thanks for the information, I really appreciate all the advice and suggestions on this site. I'm really glad I joined.

Thanks again! :yahoo: