I've been on the subcutaneous version called sayanna press before and after pregnancy. Pros are it stops my periods, I don't myself at home and it's every 12 weeks so don't have to remember something every day. Cons are that it can make my mood a bit flat and it made it difficult to lose weight xx
My period came, as usual, after 3w, but it didn't stop. I bled for the next 9w. The GP gaslighted me into having a 2nd injection and told me that my body would get used to it. I carried on bleeding, became anaemic, and needed a different hormone to cancel it out, plus iron tablets. It was awful, and I felt truly dreadful. I now refuse that, the implant and the mirena coil, as they all contain the same hormones.
I was on it pre-baby. Pros for me is that I didn’t have a period thus didn’t have cramps. Cons, I did put on weight. Doctor said that does happen but only for some people!