1) Bleeding from a uterine polyp can make a woman niddah. Based on your description here, it sounds as though you did become niddah& through the bleeding that you had prior to the biopsy. However, to be certain, we suggest calling into our telephone hotline to go through the exact details of what you saw and under what conditions.

2) Even if you are niddah, as long as you are age 53 or older, you need not observe onot perishah next month because you are post-menopausal. (If you're younger, please get back to us with details.) However, if you have two more episodes of bleeding that makes you niddah, you may need to observe onot perishah and should ask a specific halachic question.

3) No, you are not obligated to perform a bedikah after cramping of the type that, in your experience, may or may not be associated with bleeding. Do get in touch with us or a local authority in such cases for halachic guidance. You may find it helpful in the interim to review the laws of staining, as by reading our articles Stains and Toilet Paper.

Please write back with any further questions.