What Does Prolonged Menses Cycle With Low Eosinophil Count Suggest?

My girlfriend, 48, is experiencing an extended menstrual cycle (about a week beyond normal), including some clotting and tissue discharge. She just had some blood work done; the results are that she has a slightly low eosinophil count. She does take birth control pills. What could be causing this condition, what can she do to help herself, and is it cause for alarm? Thank you for your attention to this matter.