Placenta Fusing

I had OB appointment the other day and I asked him if he knew if I was having fraternal or identicals since they only saw one placenta. He said they weren't sure and during my next ultrasound (at 19 and a half weeks) they may be able to find out, if not it won't be until after they are born.
My questions are:
How soon do two placentas fuse?
And when is it too late to tell if there is one placenta or two fused together?

Thanks in advance.

 

At 10 weeks we saw two distinct sacs on different sides of the uterus with a thick membrane so they said they were fraternal (wrong as it turned out anyway, by our 16 and 20 week U/S's they said they looked fused and it looked like one big placenta. I would imagine that all twin placenta's fuse d/t the limited space in the uterus and the proximity of the growing blood vessels.

remember, if you're having same sex babies you really can't know for sure if they are fraternal or ID (unless they share a sac or develop TTS with a shared placenta)!

 

QUOTE(1stTimeMom26 @ Sep 7 2008, 10:23 AM) [snapback]967727[/snapback]
At 10 weeks we saw two distinct sacs on different sides of the uterus with a thick membrane so they said they were fraternal (wrong as it turned out anyway, by our 16 and 20 week U/S's they said they looked fused and it looked like one big placenta. I would imagine that all twin placenta's fuse d/t the limited space in the uterus and the proximity of the growing blood vessels.

remember, if you're having same sex babies you really can't know for sure if they are fraternal or ID (unless they share a sac or develop TTS with a shared placenta)!


At my 10 week ultrasound the babies were real close and there was a very thin, wispy membrane, but no mention of placenta/s or identical/fraternal. At my 12 week scan the sonographer said there is one placenta and two sacs. The membrane was hard to see, he had to look really closely. He told me there is a possiblity they are identical. Also, he wouldn't take a guess at the genders that early. So, I have to wait until my 19 and half week sonogram to find out the genders. Hopefully they will cooperate.

Since the sonographer said there is only one placenta I do worry about TTTS.
I think I'm resigned to the fact that I may not know until after they are born.

I have pictures on my blog of my 10 and 12 week ultrasounds that show the membranes, they are barely visable.

Thank you and congratulations on your baby girls. :woohoo: :itwins:

 

Don't forget if they have two placentas or two fused they still could be identical. We had a fused placenta (found out after birth) and were actually being very closely monitored for TTTS. Turned out one baby had IUGR and his placenta was dying and they didn't have a chance of having TTTS. Better safe than sorry I guess.

The only way to know for sure with two placenta's if they are fraternal or identical is with a DNA test (unless they are different sexes of course) :laughing:

 

At 11 weeks the membrane between the 2 sacs was thick, indicating they were probably fraternal, which they are (B/G).

I think that is a good indicator. What does your membrane look like on your pic??

 

QUOTE(jordynsmama+2 @ Sep 7 2008, 11:17 PM) [snapback]968635[/snapback]
At 11 weeks the membrane between the 2 sacs was thick, indicating they were probably fraternal, which they are (B/G).

I think that is a good indicator. What does your membrane look like on your pic??


At 10 weeks the membrane was very thin and wispy looking, at times we couldn't even see it. At 12 weeks it wasn't very visible at all, it took the sonographer a while to find it.

You can see my two photos on my blog page @ http://www.impregnantwithtwins.blogspot.com/

Thanks for the information. I'm having another sonogram on September 24th and I'll be just over 19 weeks, so if we see the gender and they are boy/girl, then we'll at least know they are fraternal.

P.S. Your daughter is a cutie. Congratulations on your twin pregnancy.

 

I read a study that said that it was too difficult to tell with any certainty after 11 weeks if it was one placenta or two fused placentas. If the babies are very close together, the cut-off would be earlier than that. Without an early u/s, the only way you can really tell if they are fraternal or identical is if they are boy/girl, monoamniotic, have TTTS, or with amniocentesis.

 

I have a question along the same lines----when my daughter had her ultrasound they said they think they are two boys, and they are in their own sacs, and one placenta is anterior and one posterior. Is the likelihood of them being idential less because their placentas aren't close?

 

QUOTE(mommymeg @ Sep 7 2008, 01:07 PM) [snapback]967909[/snapback]
Don't forget if they have two placentas or two fused they still could be identical. We had a fused placenta (found out after birth) and were actually being very closely monitored for TTTS. Turned out one baby had IUGR and his placenta was dying and they didn't have a chance of having TTTS. Better safe than sorry I guess.

The only way to know for sure with two placenta's if they are fraternal or identical is with a DNA test (unless they are different sexes of course) :laughing:



I remember reading about the fused placentas. I think I will have to wait until after they are born unless they develop TTTS. I hope that doesn't happen.

I think I've resigned myself to the fact I will probably have to wait, unless they are different sexes. I will have my
"BIG" ultrasound in two weeks, so maybe we will know then.

Thanks
p.s. your little guys are pretty cute

 

Those look like mo/di twins to me (that means monochorionic/diamniotic) - that also means one placenta and 2 amniotic sacs.

If it were di/di (dichorionic/diamniotic) then they would each have their own placentas and own amniotic sacs. But since its a pretty early u/s and both of your babies are in the same "dark spot" and no membrane is really visible (I know it's there but you have to look pretty hard) then you have only one placenta. One placenta also means identical. Fraternal twins cannot share a placenta. I realize that sometimes placentas can "fuse" and then can "look" like one placenta when they really aren't - in early ultrasounds those cases look like two 'dark spots' with babies in each of them. The placentas just move together and look like one later on. Maybe some other people can post their u/s pics to show you what di/di twins look like.

Your u/s looks like mine - here are my pics - note that there is no membrane visible and no "wall" between them. We didn't find the membrane until 16 weeks. We also had TTTS diagnosed at 16 weeks - I can answer your questions about that, but I would ask your dr to be on the watch for it, with u/s every other week - go to the dr immediately if you feel "off" "full" "tight" anything like that, because that's what it can feel like with the amniotic fluid imbalance (which is a sign of TTTS). In fact, with one placenta they should be on the watch for TTTS BEFORE it occurs, because they can monitor more frequently and treat it earlier. I get irritated when drs tell mo/di twin moms that they "don't know" if they are ID especially when you see an early u/s like yours. AND, they also don't watch for TTTS. Grrr.

Here are my mo/di u/s pics for my ID twins. In cases like this, I don't think you have to get a DNA test - that's really if you have di/di twins, which can also be identical, but you won't know until you get the DNA test.

8 weeks

12 weeks

I think yours are ID and have one placenta (which is how you know ID).

 

Hey,
Just sent you a PM but those are Identical for sure. No doubt there. I cannot believe your Doc or Peri wouldn't be able to tell you that?? Are you seeing a Perinatologist? Cuz you should be.. and they should know by looking at the 10 wk ultrasound. Makes me nervous that they don't... I know mine did.

You should be with a high risk doc and being monitored pretty closely at this pt.

Congrats!!

 

HA HA! I'm glad you chimed in IVFBOUND - you know we are on the same page here! Glad I'm not crazy - I thought the same as you!

 

Unless the babies are boy/girl, have TTTS, or are monoamniotic, it's really too late to tell. There was a study (I really wish I had bookmarked it <_< ) that compared the diagnosis of twin type and gestation and they saw that past 11 weeks, it is too difficult to tell if a placenta is actually one placenta or if it is fused. The doctors can make a guess but they may be right or they may be wrong.

If there is a chance that it is one placenta, you should be monitored for TTTS though just in case.

 

I'm pretty sure that at 10 weeks you can ABSOLUTELY see that they are in the same sac!! Added to the same "black hole" they are in .. the one placenta.. we get monochorionic diamniotic TWINS!!

No, I'm not a doctor but... having just been through it and having researched my butt off for a year plus.. I think I'm pretty sure.

Congrats! Can't wait to see your ids! (Yes.. that is how sure I am )

FYI-- here's a GREAT video of a set of ID twins and a frat triplet. I thought this was just AMAZING and very helpful also. Listen to what the Doc is saying too.. He seems intelligent.

http://www.youtube.com/watch?v=HQx5HYyhWZ4...feature=related

 

QUOTE(ivfbound078 @ Sep 11 2008, 02:20 PM) [snapback]974897[/snapback]
I'm pretty sure that at 10 weeks you can ABSOLUTELY see that they are in the same sac!! Added to the same "black hole" they are in .. the one placenta.. we get monochorionic diamniotic TWINS!!

No, I'm not a doctor but... having just been through it and having researched my butt off for a year plus.. I think I'm pretty sure.

Congrats! Can't wait to see your ids! (Yes.. that is how sure I am )

FYI-- here's a GREAT video of a set of ID twins and a frat triplet. I thought this was just AMAZING and very helpful also. Listen to what the Doc is saying too.. He seems intelligent.

http://www.youtube.com/watch?v=HQx5HYyhWZ4...feature=related


Sorry, I wasn't replying to your post. I just posted on the same thread twice on accident. :fool:

If you have a 10 weeks u/s, then they may be able to tell at that point. At 19 weeks it is too late.

 

I had 2 placentas fused together and they were always able to tell this on the u/s. I guess b/c one was attached at the top left, anterior and one was attached at the bottom right, posterior so it looked like 2 on the u/s.

 

QUOTE(ferfischer @ Sep 10 2008, 01:10 PM) [snapback]973654[/snapback]
Those look like mo/di twins to me (that means monochorionic/diamniotic) - that also means one placenta and 2 amniotic sacs.

If it were di/di (dichorionic/diamniotic) then they would each have their own placentas and own amniotic sacs. But since its a pretty early u/s and both of your babies are in the same "dark spot" and no membrane is really visible (I know it's there but you have to look pretty hard) then you have only one placenta. One placenta also means identical. Fraternal twins cannot share a placenta. I realize that sometimes placentas can "fuse" and then can "look" like one placenta when they really aren't - in early ultrasounds those cases look like two 'dark spots' with babies in each of them. The placentas just move together and look like one later on. Maybe some other people can post their u/s pics to show you what di/di twins look like.

Your u/s looks like mine - here are my pics - note that there is no membrane visible and no "wall" between them. We didn't find the membrane until 16 weeks. We also had TTTS diagnosed at 16 weeks - I can answer your questions about that, but I would ask your dr to be on the watch for it, with u/s every other week - go to the dr immediately if you feel "off" "full" "tight" anything like that, because that's what it can feel like with the amniotic fluid imbalance (which is a sign of TTTS). In fact, with one placenta they should be on the watch for TTTS BEFORE it occurs, because they can monitor more frequently and treat it earlier. I get irritated when drs tell mo/di twin moms that they "don't know" if they are ID especially when you see an early u/s like yours. AND, they also don't watch for TTTS. Grrr.

Here are my mo/di u/s pics for my ID twins. In cases like this, I don't think you have to get a DNA test - that's really if you have di/di twins, which can also be identical, but you won't know until you get the DNA test.

8 weeks

12 weeks

I think yours are ID and have one placenta (which is how you know ID).



I know when I had my 10 week ultrasound (it was my first...when we found out I'm carrying twins) the membrane was barely visible when the technician was looking around also there was no lambda sign at all.
Thanks for the signs to be aware of for TTTS. My next ultrasound is in 2 weeks and I know it's the one where they do all the measurements etc.
Thanks for showing your ultrasound pictures. I like to see the different ones. I've been comparing mine with fraternal twins ultrasounds and they look totally different. They have a thicker membrane and the lambda sign is present in theirs.

Thanks again.
p.s. your baby girls are dolls...so cute

 

I would put money on the fact that yours are ID and sharing a placenta.

Anyway, when you have your u/s, to watch for TTTS have them check the following (they will anyway, but take note so you can be prepared in case you want to ask questions)
Fluid levels for each baby (maximum vertical pocket should be between 2 and 8cm)
Cord dopplers (normal or not - they'll be able to tell you)
Growth discordance (over 20% diff and they start to look more)
Bladders - can you see them both?

Good luck and let me know if you have any more questions!
Jenny

 

QUOTE(aimeethomp @ Sep 11 2008, 12:30 PM) [snapback]975477[/snapback]
I had 2 placentas fused together and they were always able to tell this on the u/s. I guess b/c one was attached at the top left, anterior and one was attached at the bottom right, posterior so it looked like 2 on the u/s.


That's good to know. I wonder if they would be able to see where the placenta/s attached when I go for my 19 week ultrasound (September 24th)?

Thanks

 

QUOTE(Soon to be Mom of 4 @ Sep 12 2008, 01:12 AM) [snapback]976358[/snapback]
That's good to know. I wonder if they would be able to see where the placenta/s attached when I go for my 19 week ultrasound (September 24th)?

Thanks



There is no way that you could have two placentas. There is one

Can't wait to learn the sex!