To answer your question, YES it is perfectly safe to go on birth control pills
while breastfeeding, HOWEVER, you can not take pills that contain estrogen. There are pills call "mini-pills" or "pops" (progesterone only pills) such as camilla and micronor that are considered safe during breastfeeding. Ask your doctor about it. Some docs will give you a script straight out of the hospital, others will make you wait until you have your 6 week post partum check up.