Hello, I appreciate your concern about your periods on the implanon and what seemed like an association with Keflex. As far as I know, Keflex does not cause any changes at all in menstruation or the normal female hormones that cause you to have period bleeding
. I recommend that you go back to your primary care doctor
What you are experiencing on the implanon is quite common. Many women will experience a little bit of spotting, and then no more periods with the implanon in. That being said, it is also common for women to start having some spotting, or regular periods even, again after having been on the implanon for some time. I would say that the most common thing that occurs is what has happened to you: light spotting that then goes away, with an occasional period here and there. My best guess is that you will go back to not having periods, or just having some light spotting. That being said, every female body is different. Also, I would want you to make sure that you aren't pregnant, as heavy bleeding or spotting can be a sign of pregnancy or a miscarriage. If you are at all concerned about your bleeding, I would recommend going back to your primary care doctor or your gynecologist. They may need to see you and ask you more questions in person to further evaluate you.