You have lighter periods and fewer menstrual cramps. You do not have to remember to take a pill every day. Immediately effective after injection, there is no waiting period as with the pill. You need to use a condom with it if you may be at risk. You must visit your clinic or health care provider on time every 13 weeks for your injection.
Some women complain of soreness in the area of the injection for a couple of days afterwards.
To be this effective you must get your shot on time. This means spotting and bleeding in between your periods. After one year of use, some women stop having a period all together. This is not harmful to you, but you should make sure you are not pregnant with a pregnancy test. Some women report breast tenderness, it may be uncomfortable, but it is not considered to be dangerous.