Should you be concerned if you start bleeding 4 years after ablation?

Not necessarily: It's not uncommon for women to bleed years after an endometrial ablation. The goal is to destroy the lining of the uterus, however, given that many women have ablations done in their 30s or early 40s, hormonal influences sometimes cause gradual regrowth of the endometrium allowing bleeding to recur. No woman undergoing an endometrial ablation should be promised amenorrhea (no more periods).