Got tubal ligation last august. since december my periods have been every other month. is that normal and why could that be?

Irregular periods: Irregular periods are one of the most common problems obgyns treat. If this is one time problem it usually resolves on its own. If this is a recurring problem you should be evaluated. There are many options available to help regulate the menstrual cycle. If you are concerned about pregnancy take a pregnancy test. Tubal ligation is unrelated to periods