My first RE told me he took a deep breath before each transfer.
When I read Silbers book he spoke of the importance of using the special "floppy" catheter to transfer so there was an easy transfer and no damage to embryo during transfer. I cant recall the name of the catheter but think its standard practise to use it.
Third, when I did DE in Argentina, successful first try, we transfered one threee day embryo, and RE said after the transfer went really well. He said sometimes they are difficult, and sometimes bleed , etc and mine went well.
Having said that, that doesnt mean its all important. Its important but embryo quality is too. This is probably a question an RE could answer and I wonder if there are studies out there on it.
At some point during my cycle I had what they call a "mock transfer" where they put a catheter in and took measurements, which were noted for the RE who would do the actual transfer. That suggests to me that placement is important, although there's also no guarantee that it will stay where they put it.
I think it matters a lot. I do not subscribe to the theory that "anyone" can do a transfer and get the same results. I remember the nurses at my clinic saying that my Dr had "magic hands" as they had seen him work wonders. I believe it and would only choose to have a transfer with soemone I trust. Good luck.
I haven't done DE (yet) but have done ivf and have a history of tough transfers due to funky cervix. REs have tol me transfer is critical b/c difficult transfers can cause trauma to emryos. I've also been told that embryos and blood don't mix well.
I once had a transfer... Or shall i say atempted transfer that went on for 3 hrs before RE gave up (froze embies...they didn't survive thaw). This was after a mock. Go figure. RE says it happens "once in a career."
As long as you get a mock, you should be fine. As a precautionary measure, i have been told to come with a full bladder.