hai, i ve gone through Tubal Ligation a year back. i usually have irregular periods. but after Tubal Ligation this is my first time. i am having Primolut N for this. but to become sure that this irregularity may not be due to pregnancy(just a thought) i went for a home pregnancy test(result negative). i wanna ask that is there any possibility that the negative result is due to the norethisterone.