Norethindrone
"I love this birth control. With all 4 of my children, I start taking this pill daily 6 weeks post partum. I've nursed all my children for over a year. With my first 3, I never had a period until my child weaned around 13 months old.  My 4th is 10 month old and I just started a period. Not sure why but not worried about it.  This time we also use condoms for extra protection but we didn't with the other 3 and we never had any surprise pregnancies. Effective and I've never had any noticeable side effects other than being less moody and more even keel. Normally no cramping, spotting, nothing.  Great method for us. I'll probably continue using it after my dd weans and use condoms as well."