Shared or fused placenta in identical twins

There have been a couple threads about placentas here, and you ladies seem to be pretty knowledgeable about them. I've already had my twins, but there's one question from my pregnancy that's always had me wondering:

We found out about our twins at 19 weeks. We were told they were di-di. I assumed fraternal. When they were born, the girls we almost a full pound different in weight and there was one placenta. My midwife thought it might have been fused, but wasn't sure. It didn't look fused to me, but I'd never seen another placenta. No pathology was performed.

If my girls were fraternal, I would have chalked the weight difference up to them being different. But I've always wondered about it since I have them DNA tested, and it came back MZ.

Does this mean they shared a placenta? Can di-di identicals vary that much in weight?

 

My boys were mono/di and there was a pound difference at birth. They are believed to have had a bit of TTTS at the end because one was very red (too many red blood cells) and one was very pale (too few red blood cells.) I don't know if their size difference was attributed to that, though. I think that any twins, whether di/di or mono/di can vary in weight- I don't think that the zygosity has all that much to do with it..but I could be wrong. You are in the right place though for some knowledgeable answers...

 

I was actually getting on to ask a question similar...so I'll just add it here, if that's okay.

We had an ultrasound done today and we asked the tech if she could tell if they shared a placenta or not...we are 12 weeks, 2 days. She said that from what she could tell it looked like they shared a placenta, even though they were in separate sacs. She printed us off this picture and said that the babies are side by side with the placenta underneath them. Can the placenta fuse togeter this early or is that something that typically happens later on? ultrasound



By the way, I have no idea how she could tell anything in the pic. LOL

 

My girls were almost 2lbs different due to cord and other issues. Their membrane between them was so thin at one point they thought they were momo. the placenta could have fused or they could have had a thick membrane leading them to think didi

 

I'm curious...is the weight difference in identicals because of TTTS? So, fraternals may not have such a weight difference?

All of this is just so confusing to me. It's such an amazing experience going through it, but it's still majorly confusing.

 

These are mono di twins (or mo mo, I can't see a membrane but that's normal). They ARE sharing a placenta so you need to be seeing a high risk doctor to monitor for TTTS.

It ALWAYS makes me NERVOUS when a doctor doesn't know or tell you that!!! YIKES!

When babies are clearly in the "same black hole" they ARE sharing a placenta w/0 a doubt and you MUST be seen by a high risk doctor.

 

Identicals are more likely to be similar in weights ESP w/o ttts. With TTTs it is more likely there will be more of a discrepancy.

Frat twins can have as much of a weight difference as 2 siblings would being born at different times would. Ex. You have a son who is 9 lbs at birth. When that son is 2, you have a girl who weighs 6 lbs. Now if these two were twins and born at the same time (obviously frat twins), you would have a boy who was 9 lbs and a girl who was six lbs. Hope that makes sense. Fraternal twins are no more likely to weigh the same as two sibs would be.

 

They actually just called me yesterday after the ultrasound to tell me that I have an appointment with the high risk doc on January 5th. So that makes me feel a little better knowing that my doc seems to be on the up and up. They said that I'll probably wind up seeing more of the high risk doc than them after that appointment but they would still handle all my "routine" OB care.

 

Oh good cuz from what you wrote up there, it looked as if your doctor wasn't sure??

I'm glad you're going to see a Peri. Good!!

 

My twins were di-di and had two placentas. Around week 18 it fused. At birth twin A was 500 grams more than twin B, apparently due to infarct. They are DNA tested and ID.