Hi FG
Yes I did blasts with MIVF.

I started with John McBain and because it was my first and I knew nothing about it I did 3 day. I got 15 eggs and 8 frozen so that meant after the fresh that didn't work I had to go through 6 (of the 8 that unfroze) FET's. All BFN. I was so frustrated because as I went on I realised that of the 6 months which added heaps of pressure to my relationship and now I know most probably didn't get past day 3 plus I kept getting shunted to different doctors. I then went to his wife and insisted on a blast because personally if they are not goign to survive past day 3 - what is the point to me. I KNOW people say that if they waited till day 5 it might not have worked but their day 3 did but I have had big discussions iwth the doctor and hte fact is if they are not strong enough to get past day 3 the likelihood of going to be viable is remote. It used to be an issue because of the medium they used. They have to change the medium at day 3 and back when that wasnt perfected it caused issues but now places like SIVF ONLY go to blast.
Anyway my second stim I got 6 eggs only one made it to blast nad BFN and I was sad but you have to realise that although its hard not to think you have so many goes what is the point of wasting time.
Our third stim i got 5 to blast and the fresh took.
SIVF say if you go to blast there is a high chance you will get BFP in 3 goes.

TO be honest I would NEVER do it any other way especially if you have never been pregnant. I know day 3 works but for everyone I know that fell pregnant iwth Day 3 - they had been pregnant before - just my experience.
If I had my time over I would never have listened to the FS - and may I say I changed FS for the last stim to Manuela toledo who I cannot recommend more highly she is brilliant.
I had issues with the service before that.
BUt you need to remember this is a service- I know they are helping us - but it is a service and happy to PM you to discuss further but personally I would only do a blast. I believe it makes sense but understand why when they don't know the first cycle they try day 3...... i jsut really desperately wanted ot be pregnant so didn't want to muck around. Having said that.... I was lucky to havea blast to transfer each time. If I didn't... not sure how i would react....... Good luck !