is it normal for both boobs to have very different outputs? my left has very low supply - about 50ml per pump. my right has a very high supply - I'm not even sure how much cause I can pump 200ml and it may not be drained.

It is actually quite common to have more milk in one breast than the other. The difference could be due to different reasons such as lower glandular tissue content in one breast, baby’s preference, mother’s preference, or previous breast surgery or injury. Unless this difference is bothering you, you can actually just let it be. Otherwise, you can try to increase the supply on the other side by: - starting baby on the side with the lower supply first (switch to the higher supply one once the first side is soft) - nursing on the lower supply side twice as often (i.e. nurse on the lower supply side for two feedings, the higher supply for one feeding) - pump the lower supply side for 5-10mins after some feedings - add in an extra pumping session each day for the lower supply side You can refer to this article for more information: http://sg.theasianparent.com/causes-breastfeeding-women-milk-one-breast-can/