HI, thanks for using healthcare magic Tubal ligation does not usually fail in the vast majority of cases so pregnancy is not likely. Intermenstrual bleeding (bleeding between periods) can occur intermittently and may not indicate that there is any significant problem present. If it recurs however, you may need to see your doctor for an assessment. This would include abdominal and pelvic examination, a pap smear if one was not done recently. Depending on findings, imaging by ultrasound may or may not be needed. I hope this helps