Welcome to HCM. Any birth control tablet or implant can cause some side effects initially. Because they are purely hormonal,body will take time to adapt to the external type of hormone. It Is not dangerous,but the one thing you should be cautious is only blood during the menstruation is watery or some things else . If it is prolonged bleeding associated with normal cuts you have to be worried. Actually speaking progesterone hormone causes thickening of blood leads to thrombosis occasionally. Thinning of blood not common ,this could be due to normal anemia. Get blood HB levels. Wait for 2more months if you have still have same problem it has to be removed. Use tablet TramicMf twice daily for 3 days to control bleeding.vitamin k supplements also help. Hope this will help you. Thank you.