What Causes A Foul Odor In The Period?

I am 42 years old. During my menstrual cycle this month for the first time ever, I had a foul odor. What could cause it? There are no other symptoms and my husband and I have been together for over 23 years so there are not multiple sexual partners. If it is an infection, would it hurt to wait and see if other symptoms develop before going to the doctor?