Hi wannabemommy - I also had 3 MCs, but after I'd had DS1. Each one was early, before the end of the first trimester, but still upsetting of course.
Because I already have a known blood clotting disorder, after the 1st MC, I was told to try 100mg aspirin daily - it didn't save the 2nd one. Then I was also given progesterone pessaries to help support the pg - they didn't save the 3rd one.
What I honestly believe made the difference was having my vitamin D levels checked and corrected - low vitamin D levels are implicated in both low subfertility and miscarriage - so when I got pg with DS2, my vit D levels were well within normal range. I also had the progesterone pessaries, and had graduated from aspirin to Clexane from the day I got my positive pregnancy test - but I still think the vit D made the biggest difference.
I should say as well that I'd been taking pregnancy multivitamins and minerals, and a fish oil capsule, almost daily since being pg with DS1 - because for the first 2y I was breastfeeding, and then because we were TTC a second child. This DID NOT give me enough vitamin D. I didn't continue to take the vitamin D in the first trimester of my pregnancy with DS2, because of uncertainty from the pharmacist of its safety (most probably overcautious), but when I was re-tested for vit D at about 14w pg, my levels had dropped markedly and I was put on 1000IU a day (as well as my normal pregnancy multi and fish oil).
I hope that some of this might help you - it might also be a good idea to get the blood test for thrombophilia done to see if there is any risk that you might have that and then you can get the prophylactic anti-clotting medication, just in case your MCs involved microclots.
Good luck - I hope you get your successful pregnancy and healthy baby very soon.