If a woman gets her tubes tied is there any chance of her having another child?

My mom is 46 years old and a couple of years ago after her second child, she had her tubes tied. She said she smelled the doctors burning the tubes or whatever they do( I don't really know). Is there any possible chance of her having another child? The reason I'm asking is because she is very late on her period this month and when she went to get a mammogram, the doctors told her to get a pregnancy test. Maybe it could just be the beginning of menopause though?