Birth Control
"I have used it without scares for 17 years.  I have found my libido seriously lowered. No periods once I got past the initial 2 or 3 jabs. Worth persisting. May have some bleeding if you are late for a shot. For the first few shots bleeding can be heavy and irregular but this seems to usually settle after about 3 shots and I had no periods after that time, unless I was getting late my shot late."