Hormonal fluctuations: This is often the most common cause of vaginal spotting, especially in women of reproductive age. Hormonal changes can occur due to various reasons such as puberty, menopause, or irregular menstrual cycles.

Birth control methods: The use of certain birth control methods like intrauterine devices (IUDs), birth control pills, or patches can lead to vaginal spotting.
Infection or inflammation: Infections such as pelvic inflammatory disease (PID), yeast infections, or bacterial vaginosis can cause spotting.
Pregnancy-related issues: Spotting can occur during early pregnancy due to implantation of the fertilized egg or later in pregnancy due to placental issues.
Cervical polyps or fibroids: These growths can cause irregular bleeding, including spotting.

Cancer (cervical, uterine, or ovarian): Although less common, cancer can cause vaginal spotting and must be ruled out to avoid delayed diagnosis and treatment.
Ectopic pregnancy: This is a life-threatening condition where the embryo implants outside the uterus, often causing spotting or bleeding.
Miscarriage or threatened abortion: Spotting can be a sign of a miscarriage or a threatened abortion, which requires immediate medical attention.

Bleeding disorders: Conditions like von Willebrand disease can cause easy bruising and bleeding, including vaginal spotting.
Thyroid disorders: Both hypothyroidism and hyperthyroidism can affect menstrual cycles and lead to spotting.
Adenomyosis: A rare condition where tissue similar to the lining of the uterus grows into the uterine walls, causing spotting and heavy bleeding.
Uterine anomalies: Congenital abnormalities of the uterus can cause irregular bleeding patterns, including spotting.