Just thought I would add something else that came up in conversation with my FS about transfering two embryos that might be useful information for you, Bec.

My FS is allowing us to transfer two this cycle, and she states the reason as being due to us reaching the (slightly) lesser quality embryos in our "batch" from the stim cycle, allowing us to have a similar chance at a successful cycle as the chances in a fresh transfer, or really just the same chances as the best quality embryos used at the beginning of "the batch". FS strongly advised me not to transfer 2 embryos before now, even though we wanted to last cycle.

I'm not able to say 100%, but I certainly felt that this is something my clinic (definitely at least my FS) condones. Our embryos were frozen at day 2 and are no more than day 3 when they are transferred, so I'm sure the decision comes from that place as part of the reasoning - I don't know what their policy is for blastocyst transfers as MIVF don't usually do them.

FS spoke to us of the fact that chances of one of the embryos making it dosen't double when you have two transfered, and that when having two transfered with embryos that are statistically less likely to make it (i.e. lower quality), it helps manages the risk of twins more effectively. Say our embyro had a 25% chance of making it, then if you put two embryos that statistically have a 25% chance, then overall your chances of one making it goes up to 30 or maybe 35%, which is approximately the chances quoted to us my FS of a fresh transfer being successful. She used this as an example. With two embryos that have 25% chance each, the chances of twins is 1 in 16 (25% x 25%).

As to how they grade different quality embryos statistically, I believe it's from the data they have gathered at MIVF overall. I'm also not sure of the reason why the chances of one embryo making it doesn't increase proportionately when having two transfered - our FS just said those are the statistics and doctors are not sure of the reason why.

The reason DH and I have decided to transfer two is because we believe that the risk of twins that we have been quoted is a risk we are willing to take at the moment and we would like the best chance possible of a successful cycle, balanced with the risk of twins. This is our last cycle before moving permanently to the UK, when we are unsure of when we will next be able to continue treatment, either here or in the UK (we'll definitely be continuing treatment, but just not in the short term and not sure when yet)- so it's our last chance for now, and we'd like it to be a good chance.

Of course, I'm talking about everything statistically here, and not everyone's individual situation conforms to statistics, but as a guide, we are finding the stats useful and helpful in making our decisions.

Perhaps you can speak to Hollywood about the statistics they quote for different quality embryos, and the like - perhaps even ask your FS?

Hope this is useful, and that all the figures aren't too brain-draining!

Miss C