I'm not talking about supply, I am fully aware with the interference etc. I'm talking about interrupting the benefits of BM with a bottle of formula. I don't want to bore you with all the details as to why I'm needing to consider this, I am going to be giving bottles of expressed milk for the night feed this week to see how that goes as it's the bottle I need not the type of milk. I just really hate expressing (although I am aware I would need to either way) and was just wondering if I spoil the benefits of BF with one bottle of formula a day? I am so proud of EBF my eldest for 6 months I'm just tooing and froing, but we're having problems.