What causes ovarian cysts to rupture?

I know what causes ovarian cysts, but I'd really like to know what causes them to rupture or burst? I've been in the ER twice because I've had one rupture on both of my ovaries, one in March and one earlier this week. Could it be stress?What causes ovarian cysts to rupture?
it may be possible , depends on the type, location the size the material it contains and your age normally controlled with b/c pills, sex and hormones are the most probable reasons
I don't know what causes it ..but doesn't it hurt like he11 ?? :( I'm sick of it lol. Good luck