The suckling reflex is present earlier in pregnancy but it is known from assessing premature babies that it's usually not until around this time that the baby is strong and coordinated enough to suckle with ease. Your baby regularly practices suckling and this, in combination with the rooting reflex, will enable your baby to feed.
After birth you will see the rooting reflex as your baby turns toward anything that strokes his cheek. The head will turn, and your baby will move his mouth in a series of gradually diminishing circles until the object is found. Once feeding is well established, at about four months, the rooting reflex disappears. From this point on, your baby has much more control over the process, able to turn and directly latch on to the nipple.
While in the uterus, there is no chance of your baby accidentally swallowing amniotic fluid into the lungs. The lungs are already filled with fluid and the high pressure of this, together with your baby's larynx, keeps out amniotic fluid. After birth, babies have a series of reflexes designed to keep breathing and drinking separate. To help with feeding, babies always breathe through their nose.