I should have said, my GP who has also been through IVF a number of times told me that two teenagers at the peak of fertility have a 33% chance of getting pregant each month. It is interesting that these are approximately the same odds of pregnancy (not live birth) you have of getting pregant through IVF per cycle in the UK. These stats are based on 2/3 day embryo transfer as most clinics including my present one don't do it.

I'm just saying this to suggest that an embryo that is going to work is going to work regardless.