You're brushing your teeth and notice a bit of pink when you spit out the toothpaste. You might notice some bleeding when you floss. Although the smallest amount of blood might not seem like a big deal, if your gums are bleeding consistently, you shouldn't ignore it. Bleeding gums can happen for a number of reasons, from gingivitis to a side effect of pregnancy. Changing your oral care routine can also make your gums bleed, at least at first. Here's what you can do if you do notice some bleeding.