I had 3 MCs over the last 2 years - had a few tests, especially as I was over 40 when they were done - but not genetic tests. Basic tests were to see how fertile I still was (hormones), and my ovarian loading (good for my age) - all seemed good except I was a little low in progesterone.
So progesterone pessaries were prescribed for any positive pregnancy test. They didn't make any difference to MC no.3, though. :(
I also have a blood clotting condition (Factor V Leiden) so 100mg aspirin was suggested, just in case microclotting was an issue - again didn't make any difference to no. 3; so I was given a scrip for clexane to be started as soon as positive pg test came up.
However, mid-last year I was tested for Vit D levels because of a family history of bowel cancer and was found to be lower than I should be, so was mega-dosed by the doc to bring my levels up - and shortly after, got a positive pg test. Did progesterone pessaries and clexane straight away and luckily I am now 23w pg and have everything crossed!
I have seen research linking subfertility and miscarriage to low vit D levels - so while one anecdote does not data make, I'd like to offer it as another factor that you can remedy of it's indicated - please get your Vit D levels checked and if they're low, get some Vit D on prescription to bring your levels up. Can't promise it will work, but it's one less risk factor. :)