birth control
"I had my first shot when I was 18, I had heavy bleeding and weight gain for the whole 3 months. My doctor told me that was normal that when I got the second shot it would stop or lighten up. Well I got my second shot and it still wasn't stopping. So for a total of 6 months I was bleeding heavily. By then end of it I found out I was pregnant and had a miscarriage. I had only been about a month or two along. So just be careful and if you aren't using anything else but the shot, still pay attention to your body, and take pregnancy tests. Just to make sure. Because I got pregnant a month after I took the second shot."