Can a woman get pregnant after having a uterine ablation?

Yes . It is possible, but not preferable. Frequently ablations are combined with sterilization to avoid this possibility. If there is a concern-- take a test. If you have had an ablation and you or your partner are not sterilized, you should discuss contraception with your doctor.
Yes. It is not very likely, but it does happen. If pregnancy does occur, it usually has serious complications a reliable, permanent form of birth control is indicated prior to doing an ablation.