According to National Health Service in the United Kingdom, light periods or spotting for seven days can occur in women for a variety of reasons, including pregnancy and weight loss. Light periods are also common in women who have recently started taking birth control pills.
Healthline Networks explains that menstrual spotting and light bleeding can also be caused by underlying conditions such as infections, non-cancerous growths in the uterus, diabetes and polyps. It is important for women to consult with a physician if they experience symptoms of spotting or abnormal vaginal bleeding to ensure an accurate diagnosis. If symptoms are accompanied by fever, dizziness or severe pain, it is imperative to seek emergency medical attention.