The most common problem, and mostly about timing and who is holding the bottle. The NHS advice is to offer the first bottles when your baby is happy and relaxed, not very hungry, and that it can help if someone else gives them so your baby is not smelling your milk [1]. Other things that often work: a slow-flow teat, milk warmed to body temperature, offering a little on the tip of the teat first, and stopping after a few minutes rather than pushing through screaming. Offer a small amount every day; refusal for a week or two is normal.
Breast milk is made on demand; formula feeds that replace breastfeeds reduce production [5] [6]. Supply drops most when several feeds are replaced quickly, or when a different breastfeed is skipped each day. To recover it: go back to one fewer formula feed for a week, keep the morning breastfeed, and add an expressing session — the NHS suggests around eight times in 24 hours including at night when you are trying to build supply [1].
These come from dropping feeds too fast. Reduce breastfeeds one at a time with several days between changes so your body can lower production gradually [6] [2]. If a breast is hot, red and painful and you have a fever, contact your midwife or GP the same day.
Sometimes called nipple confusion or flow preference: the bottle delivers milk faster with less effort. Use the slowest teat you can find and paced feeding, and try to copy breastfeeding positions when bottle feeding [2]. Starting bottles after breastfeeding is well established lowers the risk [6].
Common enough to have its own page: breastfeeding guilt. One point of fact for now — in a study of first-time mothers, those whose babies had formula in hospital were more likely to stop breastfeeding early [3], which is why professionals discourage early top-ups. That is a statement about supply, not about you.
Mixed-feeding families sometimes apply breast-milk storage habits to formula. Do not. Prepared formula must be used within two hours of making it and within one hour of starting a feed; leftovers are thrown away; unused bottles go in the fridge immediately and are used within 24 hours [4].
Usually because the bottle is offered when they are hungry and upset, by the person whose milk they can smell. Try a calm moment, a different adult, a slow-flow teat, and milk that is body-warm. Some babies take weeks; keep offering a small amount daily without forcing.
It will settle to the number of breastfeeds you keep. Supply falls fastest when feeds are dropped suddenly or at random, and least when you replace one feed at a time and keep the morning breastfeed.
Some babies do start to prefer the fast, easy flow of a bottle. A slow-flow teat and paced bottle feeding reduce the contrast. Starting bottles after breastfeeding is established, around six weeks, also helps.
For a healthy term baby the main risks are practical: reduced breast milk supply, and formula-handling mistakes such as using a bottle more than an hour after the feed started. Prepared formula is a food-safety product; follow the CDC storage rules.