Change in bleeding. Many women who use implanon, a form of birth control that is implanted in the arm, find that their periods change. Some have heavier periods, some lighter, and some become irregular. Other less common side effects include mood changes, weight gain, headache, and acne.
Bleeding. After Implanon is inserted under the skin, most women complain of irregular bleeding. Even the company's literature states a 70% occurence of this irregular bleeding. When presented with this, I see very few women wanting these inserted long term.