This is called as Burping. Along with the milk, the babies swallow air also. This may vary from one baby to another and from one feed to another. Bottle fed babies swallow more air than the breast-fed babies. As the air bubble in the bottle comes up, the baby may bring up some milk also. The baby will not swallow any milk if the stomach is full of air.
Babies have to be helped to bring up the air bubble by burping them. Some babies might need burping half-way through their feed. while others happily wait till the feed is over.
To do this, the baby is held against the shoulder, and his back gently rubbed or patted till he brings up the air bubble. Remember to put a towel on your shoulder, so that your clothes are not soiled if some milk is also brought tip along with the wind. The baby can also be sat upright in the motherís lap to bring up the air bubble.
Breast fed babies swallow much less air and often do not need burping. At times, the baby goes off to sleep while taking a feed. There is no need to wake him up for burping.
You can put the baby down in the cot for a few minutes and pick him up again. Often, the change from a lying-down position to an upright one will make the air bubble come up.