Birth control options while on atkins diet?

i have been reading that birth control can stall weight loss while on the atkins diet... i was wondering if anyone knows of birth controls that do not make you gain weight, and do no affect atkins. i have extremely irregular periods, they are painfull, and i get really bad acne break outs... i used to be on orthotrycyclin lo. which helped with the breakouts and made my period regular, but i think it made me gain weight. also, if i do decided to take a oral contraceptive how do i know what pills are the sugar pills so i can avoid taking them?