# blastocyst and twinning



## lotsky (Sep 29, 2006)

Hello,


I had short protocol ICSI with our daughter where we had 10 eggs collected and 2 blasts put back- got pregnant with just DD one blast was AB and the other was BA- just the one blast worked out...
A year on we had short protocol ICSI and I am currently pg with twin boys. The blasts were both AA. 
I am an identical girl twin myself and history of identical twins in our family. 
I was wondering, as we had 2 decent blasts with Daughter put back and only got pregnant with one baby, what is the chance that these two boys are identical, i.e from one blastocyst which may have split after it was put back, or is there no chance of this and it must be fraternal. 

Im not too bothered either way, but would find it interesting to know if identical twins can occur with a blastocyst, or would an embryologist see this before putting them back and therefore advise accordingly. 

So far it looks like they do have seperate sacs from the ultrasounds.

At the beginning of my pregnancy i had many echos due to OHSS, and one gestational sac appeared a whole week after the other, I was therefore wondering if potentially a few cells could have broken away from one blast, and therefore put one baby behind the other while its cells doubled up and caught up.....if you know what I mean?

what do you think~


Thanks for making this board open again!

Lotsky x


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## CrystalW (Jul 25, 2007)

lotsky said:


> Hello,
> 
> I had short protocol ICSI with our daughter where we had 10 eggs collected and 2 blasts put back- got pregnant with just DD one blast was AB and the other was BA- just the one blast worked out...
> A year on we had short protocol ICSI and I am currently pg with twin boys. The blasts were both AA.
> ...


Hello Lotsky,

Congratulations on your on-going pregnancy. You may want to ask a midwife as well.

Blastocysts do have a slightly higher identical twinning rate than putting them back at a earlier stage - usually its about a 3-4 % chance.

So there is a 96-97% chance they are non-identical when two blastocysts are put back.

Usually seperate sacs also means non-identical but whoever scans you should be able to confirm they are non-identical.

I am not too sure about the second sac appearing a week later. Not all embryos develop at exactly the same rate and it may have been difficult to scan you exactly.

Good luck with everything.


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