Your child suddenly refusing their bottle can result in a great deal of worry for new parents, especially when your child can't yet tell you why. Although there's no one single answer to this problem, a variety of solutions available are fairly simple in nature.
Have You Recently Stopped Breastfeeding?
If you've recently started weaning your baby from breastfeeding they might resist being fed from a bottle. This is often referred to 'nipple confusion' and is a very common reason for bottle refusal. Your child simply doesn't understand (or like) the object being offered to them instead of your breast.
One solution is using a breast-like bottle as opposed to a more alien, unfamiliar one. I've found it also helps to have someone else (who your baby doesn't associate with prior breastfeeding) offer the bottle. If that doesn't work, give it time breast weaning is a process, and it might take a bit of time for your child to be fully comfortable with a bottle.
Could It Be Your Position?
Tying into the above, a recently weaned baby may be confused by their position at feeding time. One very common way to feed your infant is by cradling them in your arm. This has been known to cause confusion, as your child expects your breast but is instead presented with a bottle.
Try out different positions each time. Walking around while feeding has often helped me, usually with a baby sling so neither of us gets tired. Other babies may prefer being held upright on your lap, or even holding the bottle themselves if they're capable.
Are You Overfeeding/Underfeeding?
Babies are finicky, and it could be that they have already had enough to eat already and doesn't want anymore. That, or it's been too long since your baby's last feeding and they are too cranky to accept the bottle.
How much your child should be eating varies by age. I've had the best luck with this article (source). If you're not sure about what/when your baby should eat, speak with their pediatrician.
[ Read : Can you overfeed a breastfed baby? ]
What Temperature is the Milk?
The milk you feed your baby should be roughly body temperature (that is, 98.6 F or 37 C). There is wiggle room, however, and all babies have their own preference. Milk that is just right for one baby may be slightly too warm for another, or just a little too cold.
Try out slightly different temperatures at each feeding. There are a variety of ways to do this. Try freezing the milk beforehand, thawing it overnight in the fridge, and then placing it under warm running water. There are also bottle warmers if you'd like to keep things simple.
Never use a microwave to warm the bottle, as they tend to heat unevenly and can cause patches of milk that are far too hot, risking potential burns. Sooner or later you will find the temperature that is just right for your baby.
5. How Quickly Is The Milk Flowing?
Your baby may be refusing their bottle simply because the size of the nipple restricts milk flow, or lets the milk out far too quickly. Again, every baby has their own preference. Your child might find it frustrating to suck on a very slowly flowing bottle, or they might be overwhelmed by how quickly the milk comes out.
Test how quickly your baby's bottle flows by holding it upside down and letting it drip. While every baby has their own specific preference, one drop per second is generally recommended. Start with this, and if they still refuse the bottle, try out different rubber nipple sizes until you find one that is just right.
6. What Is The Environment?
Babies are far more easily distracted than we are. While it might be easy for you and me to tune out intrusive noises while eating a meal, a baby hasn't had time to learn this strategy yet. Something as simple as a television or a loud radio is enough to overwhelm your baby if they are trying to eat at the same time.
This is, for the most part, very easily dealt with. Make sure there isn't any stimuli that may overwhelm your baby at mealtime. Turn off the TV, lower any music, and make sure any surrounding conversation is at a low volume. This way your child will be able to focus on their bottle and only their bottle.
7. Does Your Baby Have Trouble Sucking?
Some babies have trouble sucking on a bottle, especially if they have recently been weaned from the breast. If they're accustomed to a human nipple and have suddenly been presented with a bottle, they may struggle with sucking in a slightly different fashion than before.
It helps to find a rubber nipple that is as similar as possible to your breast. Some manufacturers even produce rubber nipples specifically modeled after human nipples, areolas and all! If your child struggles with sucking in general and is old enough to handle a sippy cup, consider purchasing one specifically designed not to spill.
8. Is Your Baby Sick?
If all else fails, it may be time to visit your child's doctor. Various illnesses, such as ear/throat infections and the common cold, cause discomfort when swallowing and may be the reason your child is refusing their bottle. If your baby exhibits any symptoms of illness, make sure from a licensed professional that it isn't something serious - after all, it's always better to be safe than sorry.
There are many reasons your baby may be suddenly refusing their bottle, most of them easily rectifiable (recent breast weaning, position, food quantity, temperature, speed of flow, environment, difficulty sucking), though you should always have an eye open for something more serious, such as illness. If you play around with milk preparation and bottle presentation you're more than likely to eventually settle on the right combination.