Does placement of placenta in womb mean fraternal versus identical?

My daughter had her ultrasound a couple of weeks ago, and they think she is carrying two boys. The tech said they are each in their own sac, with their own placenta. She also said one placenta is anterior, and one posterior. Does that make the likelihood of them being identical less? If the egg split and they each developed their own sac and placenta, would both placentas be placed side by side or closer together? The ultrasound tech also said they are fraternal........which from the knowledge I have learned here, I dont think she can say that absolutely. Am I wrong?????

 

I am pretty sure it does not matter. I have id (own sack own placenta).

Congrats to your daughter!

 

Since there is a greater chance of having fraternals in every twin pregnancy (frats are more common) and they do not share a placenta, I would be "prepared" for them to be fraternal. For some people this is kind of sad, as they hoped for identicals (more "twinny" in a way), and they feel a bit let down when they see how different their babies look.

I know for me it was strange, although I also had a placenta on each side and knew that the odds were high for mine to be fraternal, to see how different my boys were. One very fair, one very dark.
Today I wouldn't have it any other way (of course) but they were much less twinny than expected and I did feel a tiny bit cheated, that I didn't get identical twins. Today I feel a bit ashamed about that, actually.
Millie

 

You're right, the tech is wrong. I had fundal anterior and low-lying posterior. They don't get any more distant than that... and the DNA test says ID.

 

Doesn't matter where they are positioned.

I have fraternal girls, they both were in their own sack and own placenta. Everyone in my family that had twins had fraternals. My girls couldn't look more different from each other. One is blonde with reddish highlights that is peg straight. The other is dark brown and very curly.

 

QUOTE(debid @ Sep 10 2008, 09:37 AM) [snapback]972939[/snapback]
You're right, the tech is wrong. I had fundal anterior and low-lying posterior. They don't get any more distant than that... and the DNA test says ID.


How did you get your DNA test? Is it something that you get done while in the hospital, or later. Just wondering?

 

QUOTE(seamusnicholas @ Sep 10 2008, 09:29 AM) [snapback]972920[/snapback]
I am pretty sure it does not matter. I have id (own sack own placenta).

Congrats to your daughter!


Actually, I think our situation is just the opposite. My SIL WANTS them to be fraternal so he can tell them apart! I think he fears being embarassed if he wouldn't know his own children apart! (haha)

 

No, I meant does not matter where the placenta is located!

I got my dna test from proactivegenetics.com

 

Here is how it works:

Identical twins can have:
2 sacs and 1 placenta (safest for the twins)
1 sac and 1 placenta (this is how siamese twins happen - but many twins are born this way not attached)

The 1 or 2 sacs is based on how far into gestation the egg splits.

Fraternal twins always have:
2 sacs and 2 placentas

The egg does not split there are 2 eggs fertilized from the start.

Does that help? My doc explained this to me when I asked her if my twins were id or frathernal at my 18 week visit .

Sarah

 

QUOTE(SCC @ Sep 10 2008, 10:12 AM) [snapback]973016[/snapback]
Here is how it works:

Identical twins can have:
2 sacs and 1 placenta (safest for the twins)
1 sac and 1 placenta (this is how siamese twins happen - but many twins are born this way not attached)

The 1 or 2 sacs is based on how far into gestation the egg splits.

Fraternal twins always have:
2 sacs and 2 placentas

The egg does not split there are 2 eggs fertilized from the start.

Does that help? My doc explained this to me when I asked her if my twins were id or frathernal at my 18 week visit .

Sarah


Or IDs can have 2 sacks and 2 placentas if the egg splits in the first three days. This was my situation. I think 20% of ID's are this scenario.

 

QUOTE(SCC @ Sep 10 2008, 10:12 AM) [snapback]973016[/snapback]
Here is how it works:

Identical twins can have:
2 sacs and 1 placenta (safest for the twins)
1 sac and 1 placenta (this is how siamese twins happen - but many twins are born this way not attached)

The 1 or 2 sacs is based on how far into gestation the egg splits.

Fraternal twins always have:
2 sacs and 2 placentas

The egg does not split there are 2 eggs fertilized from the start.

Does that help? My doc explained this to me when I asked her if my twins were id or frathernal at my 18 week visit .

Sarah


You missed something. ID twins can have 2 sacs and 2 placentas. 2 placentas is actually the safest kind of twin pregnancy since there is no risk of TTTS.

I got my DNA test from affiliatedgenetics.com. It's just a cheek swab -- zero pain and you do it at home then mail in the test kit. I paid about $150. It might not be needed, though. It could be that the boys will have different blood types or other obvious genetically-determined differences. The tricky part comes when they look very much alike but not completely because of differences that are not genetically-determined. Things like dimples, amount of hair at birth, head shape, and whether or not they have jaundice or other complications can make ID twins look different. I've never had any trouble telling mine apart.

 

QUOTE(SCC @ Sep 10 2008, 10:12 AM) [snapback]973016[/snapback]
Here is how it works:

Identical twins can have:
2 sacs and 1 placenta (safest for the twins)
1 sac and 1 placenta (this is how siamese twins happen - but many twins are born this way not attached)

The 1 or 2 sacs is based on how far into gestation the egg splits.

Fraternal twins always have:
2 sacs and 2 placentas

The egg does not split there are 2 eggs fertilized from the start.

Does that help? My doc explained this to me when I asked her if my twins were id or frathernal at my 18 week visit .

Sarah


This diagram helped me understand the fraternal versus identical process. http://library.med.utah.edu/WebPath/PLACHTML/PLAC101.html

 

Also you can't go by the blood type, my peri and the hospital said this to me. I know it's true because my girls have the same blood type and my son has different. I am A-, DH is O+, DS is A+, DD's are O-. All our kids are a perfect blend of our blood types, but my girls are definitely the same.

 

we have ID girls and at our 10 week US the placentas were on opposite sides of the uterus and there was a thick membrane separating the sacs, but the girls are still ID

 

The sono tech originally said that my twins could be ID b/c of the thin membrane separating the 2 sacs....and b/c they were both girls (found out they were girls at 20 weeks)...not the case, they are definitely fraternal... when they came out......One was fair, one had olive skin, and one had dark hair, the other lighter...Also, fraternals run in my family (always genetic component) and I am expecting a second set of twins in March.....