Women can spot blood due to ovulation, early pregnancy, and as a reaction to taking anticoagulant medications. One of the most common reasons for spotting is ovulation, which typically occurs halfway between the menstrual cycles. During ovulation, the ovary releases an egg, and when this occurs, slight pain and a small amount of vaginal bleeding can occur, according to WebMD. This is a harmless condition, and warrants no treatment.
Spotting can also occur as the result of early pregnancy, according to What To Expect. This is also known as implantation spotting, and refers to the implantation of the embryo into the uterine wall. Women may also spot blood after intercourse; this is usually related to the rupture of small, fragile blood vessels.
Vaginal bleeding or spotting may also occur when women take anticoagulant medications such as aspirin. Anticoagulant medications inhibit the release of prostaglandins and may inhibit platelet aggregation, according to the Cleveland Clinic. Because of these mechanisms, abnormal bleeding can occur, including bleeding from the vagina, as well as bleeding from the gastrointestinal tract, mouth, nose and urinary tract.
While mild, occasional vaginal spotting is typically no cause for concern, prolonged spotting or frank bleeding warrants further investigation. Heavy vaginal bleeding may be related to hormonal imbalances, benign uterine fibroids, ovarian cysts, or in some cases, cervical or endometrial malignancies, according to Medline Plus.