My gums bleed after i brush my teeth. how can i prevent this in the future?

A lot or a little?: Sometimes, accidental trauma will cause tiny point bleeding on your gum. That would be normal. However, if spontaneous bleeding occurs every time you brush, this would indicate an underlying periodontal disease that needed to be diagnosed and treated. Good brushing will always help the bleeding but will not treat the disease. Check with your dentist/periodontist.