Infertility questions!!!!

Hello All, my husband and and I are trying to conceive but have had 3 miscarriages in a row my ob has now referred is to a fertility doctor which we see on the 6th of March. I can get pregnant but for some reason I can no carry past 6 weeks. I have had labs and testing done and everything comes back normal we have now been trying 2 years. Has anyone else had a similar problem and what was the treatment plan? I know everyone and every doctor is different just trying to get some advise to ease my mind... Thank you in advance!!!