Hello Thanks for trusting us with your health concern. After tubal ligation, pregnancy is very remote a possibility. There could be other reasons for the spotting. True, it coincided with implantation, but I still think that after tubal ligation, other possibilities must be considered first. The leading common reasons are - anxiety, stress, tensions, late nights, erratic eating habits, smoking, drinking, alcohol, drug abuse, ingestion of hormonal medications, weight gain or weight loss, travelling, change in climate or altitude, recent illness, surgery or flu etc. Other than that, get your TSH levels checked. Hypothyroidism if uncontrolled also can lead to erratic spotting. Polycystic ovarian disease and endometriosis or a polyp should be ruled out. Get a gynecological evaluation, hormonal assessment and a pelvic transvaginal ultrasound scan if the spotting recurs. All the best. Take care.