PROBLEMS WITH GIVING FORMULA
Giving formula once the baby is a bit older, perhaps after the middle of the first year when solids are starting to be introduced too, is a lot less problematic than mixed feeding a very young baby. Your supply will be well established and less likely to be adversely affected, and it's less likely baby will get nipple confusion. In a slightly older baby still, perhaps 9 or 10 months, they will presumably by now be eating a fairly varied diet, and may already have had cows milk in other forms. Some people do run into problems with nipple confusion or intolerance of course, but the older the baby the less likely this is. In a younger baby, particularly if you have a family history, then adding cows milk products into baby's diet increases the risk of allergy and atopic disease in the baby, and there is some evidence that introducing even small amounts of formula affects the bacteria in baby's gut, and undermines some of the benefits of breastmilk.

SUPPLY ISSUES
Fiona says: “Personally, I never had supply problems. I continued to breastfeed whenever we were together and never actually gave a bottle myself. I did get a bit uncomfortable towards the end of the working day, especially after a weekend, but she never seemed to go short! I've since had people tell me that this can't be right, it shouldn't have worked etc and that I should have kept to the same pattern every day. Maybe that's right for some people, and maybe what I did doesn't work for everyone. But I just did what came naturally to me - when she asked for milk I gave it to her!”

With a younger baby, supplementing baby's milk feeds with formula rather than the baby being breastfed could quite possibly affect supply. As you probably know, milk is made on a "supply and demand" basis, stimulated by the baby suckling. If the baby isn't hungry, because they have had a formula "top up"feed, then they won't ask to be fed. So the mother's body is getting the message that it needs to make less milk rather than more. So when he is hungry, the supply is down. So you give him a bit more formula. And so on.... Lots of new mums get into this cycle, and it can be difficult to break, so they end up stopping breastfeeding much sooner than thay wanted to. Of course for some mums and babies who are having major problems, formula can be really helpful, but in general terms "top ups" probably cause more problems than they solve. Now you will no doubt meet people who say they mix fed from very early on and had no problems. True. For some people it seems to work just fine, but not for everyone. In fact probably not for most where it is started in the very early days.

OTHER RISKS OF GIVING FORMULA
Fiona says: "I wouldn't criticise anyone for mixed feeding - I've done it myself when I went back to work after my first baby. But there are some potential downsides, namely the risk of nipple confusion and possible supply reduction. It certainly can work, but there are potential disadvantages, and the younger your baby is when you do it, the greater the risks. I'm afraid lots of people who go for mixed feeding early, do end up fully formula feeding sooner than they might have wished. I'd encourage you to get some expert help".