4 very early m/c. 3 intramural fibroids, largest 3.4cm. can intramural fibroids smaller than 5cm cause very early recurrent miscarriages?

Not usually : Fibroids are not common causes of recurrent miscarriage. You should ask your doctor about testing for anti phospholipid antibody syndrome and thrombophilias.

Yes: Yes, but only if they distort the endometrial cavity. A sonohysterogram or hsg could help figure this out, and if affecting the uterus a myomectomy is very effective restoring you anatomy and reducing your risk for miscarriage.