Does Birthmark Cause Any Medical Issues?

29 year old, 5'6", 192lbs no significant medical issues. Have had a birthmark on leg for as long as I remember it's 8mm vertically and horizontally, all brown with flecks of dark brown that have not changed. It's large has irregular borders, has always grown hair, and is smooth and flat like my skin --- is there any cause for concern or is this most like a standard atypical mole I shouldwatch. I have started taking photos monthly and so far no change since last month...