Mind you the implant also has hormones (Implanon has Etonogestrel only). In Germany it is hardly used, don't know why though, it's been on the market since 2000. Peral Index can't be given yet, but seems to be high, approx. like pill.
Here a new thing has come up in the last year: a ring (Nuva Ring, no latex) which is full of hormones. It gets put in a bit like a diaphragm and is left in for 3 weeks. The hormones get released and because the stuff does not go through your digestive system (hormones are absorbed through the mucus tissue of the vagina) you need less hormones.
It works similar to the micropill with "Etonogestrel" (=Gestagen) and "Ethinylestradiol" (=Estrogen) not letting any ovulation take place + the mucus in the cervix is less penetrable for sperm. After 3 weeks you pause for 7 days -> bleeding occurs -> start again. You can go on withouut the 7 day pause and forget about bleedings.
Pearl Index: 0,4 - 0,65; slightly less than the pill.
Might be an alternative to people who forget to take their pill on time.