Hi
Dr. Purushottam welcomes you to HCM virtual clinic.
I have gone through your query. 
I think I have understood your concern, I will try to suggest you the best possible treatment options.
It appears from your history that you are trying to get pregnant over last 4 years.
I would like to know, what was thw period of last 
pregnancy when you had 
miscarriage. If it was before 12 weeks and did you undergo curretting. 
Also if your cycles are regular you need not worry.
I will suggest you to know patency of tubes by doing sono - salpigography or 
Hysterosalpingography. In these tests saline or dye is pushed through 
uterus and tubes and it's spill is seen. Also get semen count of your spouse done.
Adopt healthy life - proper diet and exercise, add 
Folic acid and B 12 supplements.
I hope my answer helps you.
Thanks.