My LO is 10 months old and this week, I am taking an L3 medicine with which nursing is not recommended. I am still nursing her but waiting until 6 hours after taking each dose to nurse to try to minimize the amount that is in my system when she nurses. (This is after talking with the people at Infant Risk regarding my medicine.) Anyways, I have no clue how to replace nursing with formula during the hours that I can't nurse. Is one ounce of breastmilk equal to one ounce of formula? Or does it take more/less formula to equal breastmilk? So far, I have replaced it ounce for ounce. But I noticed that the formula container has instructions for mixing up an 8 ounce bottle. The most breastmilk my LO has ever drank from a bottle in one feeding was 4 ounces. That made me wonder if maybe I am supposed to give more formula than I would breastmilk. I just want to make sure she is getting enough nutrition!
Also, I only occassionally give my LO a sippy cup of water since she has been EBF and I didn't think it was really necessary. Once she is drinking more formula, is it more necessary for her to drink water? I've heard water is more important for formula-fed babies than for nursing babies.
I know this a forum about breastfeeding but hopefully someone here can help me figure out how this formula stuff works! I know I am not the first mother to need to replace some nursing sessions with formula. Thanks!