coopde I thought I'd just chime in here and second what duggs is saying. I'm not doing IVF, but from a testing point of view, much as I really like Mr S and hold him in high regard, there are quite a few things he doesn't test for that Dr G (and others) do - and they can all have a huge impact on your fertility/ability to get/stay pregnant. I hear you about the time pressure - no-one more so than me! - but honestly you need to know that you're not wasting your energy in doing IVF and all the strain that goes with it if you have other issues that are thwarting you. If your eggs are fine, and your OH's sperm is fine (has it been tested for DNA fragmentation, btw? doesn't show up in normal tests), then yes it might be high NK cells stopping you - but it might be something else alongside them too. TNF-a, DQa, hidden infections, LAD count, all may be relevant (and there may be other things too).
Not presuming in any way to tell you what to do, obviously!, just that there are other things that Mr S doesn't routinely test for that may potentially be having an impact.
And 38 is still young ... I had my DD 2 days before my 39th birthday, and she was a complete accident, I hadn't been TTC at all, just a one-off that really shouldn't have happened (but obviously now I'm glad it did!). Ok, so I'm struggling for a second - but I'm a lot older, and have issues now that I clearly didn't have back then. All I'm saying is, time isn't really against you yet, so you could possibly afford to take a bit of time to make sure you have the complete picture, IYSKIM.
/waves to everyone