As babies gain control over their muscles, these reflexes gradually disappear. (If they don't, consult your pediatrician.) Meanwhile, observing them during the first few months can reassure you that all is well with your infant's neurological health.
STEPPINGA healthy baby will move his feet up and down, as if he's marching, when held under the arms in an upright position. (Be sure to support his wobbly neck muscles.) You can also provoke this response by brushing the top of his feet or letting them touch a flat surface, but doing so won't help him learn to walk any faster. In fact, the reflex usually disappears after two months.
STARTLING"When a baby suddenly flings her arms out, then pulls her hands back to her chest with a jerk, that's the Moro, or startle, reflex," says Catherine Dundon, M.D., a pediatrician at Vanderbilt Children's Hospital, in Nashville. A newborn may display the Moro reflex in response to a sudden change in temperature, such as when you're changing her diaper, a loud noise, or a vigorous movement -- when you scoop her up unexpectedly, say. The Moro reflex may be accompanied by an arched back. This reflex too goes away after a couple of months.
SUCKINGA newborn will automatically suck on your finger if you put it in her mouth. This urge is so strong and develops so early that some babies are born with a blister on their lips from having sucked on their fingers while in the womb. The ability to suck ensures that new babies will get nourishment to survive from either a breast or a bottle. But as they become more conscious of the comfort it brings, they'll suck on a thumb, pacifier, or toy to calm themselves.
ROOTINGHold a newborn at his mother's breast and he'll turn his head toward the object of his desire -- milk! You can also induce this reflex by stroking your baby's cheek, says Dr. Dundon. As though a breast is there, he'll turn toward the source of touch. So when feeding your infant, don't work against this reflex by trying to push the baby's far cheek toward the breast or bottle. Instead, stroke the cheek nearest the "target" breast to get his head to turn toward it. At around 4 months, the rooting reflex should disappear.
"FENCING"When a newborn turns her head to one side, her arm on that side straightens out, while the opposite arm bends up in an "en garde" position (sometimes called the "fencing posture"). If this particular reflex persists, it can indicate a neurological condition, such as cerebral palsy, so parents who observe their baby doing it beyond 5 to 7 months should alert their pediatrician.