It really can be a problem. When my ds was born I topped up with formula (long story, milk slow to come in after emcs, he lost 15% of birthweight). I started off cup feeding him but this was slow and messy and dh just could not get the hang of it at all. Giving him his extra ounce in a bottle seemed much easier and quicker, he certainly was happy to take the bottle.
The first feed he fed well at the breast, then had a bit of ebm from the bottle. Second feed, fed ok, then finished a whole ounce in a bottle. Third feed, fussed a bit at the breast, then guzzled all that was in the bottle (another ounce and a bit or something). Fourth feed, just played at the breast.
I dumped the bottle and went back to the cup for top-ups (only needed them for a week or two, more because of dented confidence as he started putting on weight the same day he got his first top-up, milk came in at the same time) and we were fine thereafter. It would have been very easy to think that the bottle was the best / easiest option though. If I'd kept offering the bottle I think I'd have stopped bfing within the week.
Ds was a week old at this point, btw.
Sorry this has been a bit of a ramble, have condensed it as much as i could.
The following is from kellymom.com
- There is no such thing as nipple confusion.
Not true! The baby is not confused, though, the baby knows exactly what he wants. A baby who is getting slow flow from the breast and then gets rapid flow from a bottle, will figure that one out pretty quickly. A baby who has had only the breast for three or four months is unlikely to take the bottle. Some babies prefer the right or left breast to the other. Bottle fed babies often prefer one artificial nipple to another. So there is such a thing as preferring one nipple to another. The only question is how quickly it can occur. Given the right set of circumstances, the preference can occur after one or two bottles. The baby having difficulties latching on may never have had an artificial nipple, but the introduction of an artificial nipple rarely improves the situation, and often makes it much worse. Note that many who say there is no such thing as nipple confusion also advise the mother to start a bottle early so that the baby will not refuse it.