Birth Control
"My doctor recommended Nexplanon after I got pregnant while on Nuvaring, but later miscarried. The first few months were great, the first month I had a normal period and then none yay!  Month 4 brought on a pain in my right lower abdomen that was terrible along with bleeding black blood.  My PCP was out so I ended up at a walk in clinic where I found out this lovely birth control caused ovarian cysts. One had ruptured leading to the bleeding the other needed to be removed surgically.  Apparently this is a very common side effect."