I'm sure you all have seen this question before, but I'm not sure where to find it among the many posts. I am starting to prepare for my 5th transfer using DE. We have transferred 5 total embyros so far - 2 in the States to start using frozen; then 1 fresh transfer at Zlin in CR and finally 1 more frozen at Zlin. Out of it, I have had two chemical pregnancies and two BFNs. I am 46 and in good health, all blastocysts were quality and my lining/levels were good for all. So, implantation is the issue at this point. We were not given any recommendations from either clinic until after the most recent failure. Zlin mentioned another diagnostic hysteroscopy (i had one in 2016 and there are no fibroids/polyps), thrombophilia and immunology testing. I've also read about the natural killer cell testing. We are now looking at clinics in Spain, as I thought I read somewhere success first occurred in Spain and they've been doing IVF the longest (not sure if this is accurate or not). Can you ladies please offer your insights on which clinic in Spain would be the best to work with considering my circumstances (age, mutliple failed transfers, otherwise normal health). We talked with Dr. Skinner at the Barbados clinic the other day and she said people with normal health can still have immune system issues and suggested the NK testing, but I've also heard this expensive test can come back with no issues and I'm still back at square one. I'd like to consult with another experienced doctor at a clinic in Spain. Just trying to narrow it down. Any help is much appreciated!