I got them both times. With Mya i never knew what was wrong with my bum till about 4-5 weeks after she was born & i told a friend & she said it was hemroids haha! U can get this gel stuff from the pharmacy which clears them up really fast. With Bodhi i had hardly any. The hospital gave me some cream, then i went & got the other stuff from the pharmacy & they healed up really fast.
I have no idea if they are preventable. Its worth looking into tho-----coz they can bloody hurt!