Hi, Lisa. Some reasons for vaginal bleeding after hysterectomy include vaginal dryness, "mini periods", menopause, and insufficient hormone replacement therapy. Vaginal dryness, a common side effect of hysterectomy, makes vaginal tissues thinner and more prone to bleeding from sexual intercourse or other irritations. One can even develop fissures, or cracks, in dry vaginal tissues that cause bleeding. “Mini periods” can continue if you had a subtotal hysterectomy and the cervix was retained. Essentially, a tiny portion of uterus remains, and as the ovaries continue to cycle, that small piece of uterus continues to shed lining just as before. Menopause also still comes to those who have had hysterectomies but retained one or more ovaries, and the hormonal changes might cause vaginal dryness and slight spotting from time to time. Similarly, hormone imbalances from insufficient hormone replacement therapy (HRT) can cause the same types of issues.
A quick pap smear or biopsy will let you know if any abnormal cells are present and further investigation is required. If it is simply vaginal dryness, estrogen cream or lubricants might solve your slight bleeding easily.