My clinic's pre-transfer protocol always includes prednisone for about 5 days prior to transfer.
I've had immune testing done a couple of years ago and was considered borderline. We subsquently added Lovenox and intralipids therapy to my protocols, then later extended the length of time taking prednisone-at my request, still nothing, not even a chemical after multiple transfers with genetically tested, top-graded day 5 embryos.
In November I had an endometrial biopsy following Dr. Kliman's Endometrial Function Test protocol. Your RE's office can ship samples to his lab at Yale. His method is to look at lining cells during a 'normal' cycle and then again after you've started to take the progesterone and estrogen supplementation that is typically prescribed prior to transfer. Abnormal cells were discovered in my second biopsy. Based on these results, my protocol was altered to use a lower and slower introduction of progesterone pre-transfer. I transfered two un-tested blasts (I couldn't afford genetic testing this time) and both took. I'm 10.5 weeks along.
I first turned to DE in 2009 and only now acheived pregancy. I'm convinced that this change to progesterone adminstration (lower doses delivered vaginally instead of using intermuscual injections)was the key to success for me. Certainly this may not be the case for you, but why not do the EFT to rule out if you have any lining issues at the cellular level?
You and your DH can check out this site for more information on the EFT:http://info.med.yale.edu/obgyn/kliman/.
There are articles geared to both patients and physicians.