Levonorgestrel
"Switched from combination pill to mirena after 5 years on the pill. I'm 27 and have never been pregnant.

The insertion was. the worst thing I've ever experienced ! Almost fainted. The following 8 hours I had really bad cramps (never really had them before), I'd say a 8/10. Also threw up six times and got diarrhoea. Strange! The following 5 days light spotting, then light period (as planned) for about a week. 

It's now been almost 8 weeks since insertion, got my second period which was very light compared to being on the pill. Apart from the horrible insertion I'm very content with mirena, absolutely worth it! Also much cheaper as my pill cost around $10 each month and the mirena only $70 for five years, perk of living in Sweden."