Started yasmin the birth control pill over a week ago and suffering light bleeding after intercourse is this because of the pill or because of the intercourse?

Intercourse doesn't cause bleeding unless you have an alteration in your vagina's inner tissue, that only a gyno can tell you, after an appropriate examination. Other cause may include lack of natural (from your partner) or artificial lubrication. About Yasmin, you can either talk to your gyno or to your pharmacist of confidence and try to take another brand which presents a different formulation. Have you already taken the Papanicolau test? Do you feel any pain on your abdomen?