Sino po dito naka Depo/Injectable? 100% safe po ba talaga sya?

I have friends and officemates na naka injectable. I know they do it every 3 months. Generally, safe sya pero I read once sa news na naka depo pero nabuntis. I don't know what happened pero parang error sa part ng gumawa so you also have to be careful kung saan kayo mgpapainject.