If your gums bleed when you brush or floss; even if there is no pain-you should be concerned.
Healthy gums should NOT bleed during brushing, flossing and even during a professional clean at the dentist.
If your gums are bleeding, even a little, you need to see a dentist. It can be early signs of gingivitis or worse, periodontal (gum) disease. We now know that there is a link between gum disease and heart disease, low birth weight and premature babies.
The absence of pain does not mean that all is well, often gum disease may not be painful till the more advanced stages where tooth loss is more likely.
If your gums are bleeding, you need to arrange a visit to the dentist to have a further assessment. Often, it may just be a correction in your brushing or flossing technique and a professional clean that can prevent more severe problems.