Ay, this is tricky kasi delayed period after tubal ligation can happen, pero one month is quite a stretch na, maraming possibilities ito from hormonal changes to stress to other reasons talaga. Best na checkup ka with your OB para ma-rule out kung may iba pang nangyayari, kasi two years na tubal mo so unlikely na related na yan directly sa ligation itself. One of my mum friends had irregular periods years after hers and turned out stress + hormonal imbalance lang, pero important talaga na confirmed mo with doctor mo kung ano talaga ang cause, sis!