What could cause light spotting for a month? 30, healthy, no birth control and not sexually active with very irregular periods. thanks!

2 ideas: I typically divide irregular bleeding into 2 categories. One is architectural, there's a polyp or fibroid in your uterus causing irregular bleeding. The other is hormonal, your balance of estrogen and Progesterone is off. Other ideas are thyroid and pituitary. Your doc can run tests to check all of these. Extremes of weight can also cause. Best of luck finding an answer!