Newborn Reflexes

Much of your baby’s activity in her first weeks of life is reflexive. For instance, when you put your finger in her mouth, she doesn’t think about what to do, but sucks by reflex. When confronted by a bright light, she will tightly shut her eyes, because that’s what her reflexes make her do. She’s born with many of these automatic responses, some of which remain with her for months, while others vanish in weeks.

In some cases, reflexes change into voluntary behavior. For example, your baby is born with a “rooting” reflex that prompts her to turn her head toward your hand if you stroke her cheek or mouth. This helps her find the nipple at feeding time. At first she’ll root from side to side, turning her head toward the nipple and then away in decreasing arcs. But by about three weeks she’ll simply turn her head and move her mouth into position to suck.

Sucking is another survival reflex present even before birth. If you had an ultrasound test done during pregnancy, you may have seen your baby sucking her thumb. After birth, when a nipple (either breast or bottle) is placed in your baby’s mouth and touches the roof of her mouth, she automatically begins to suck. This motion actually takes place in two stages: First, she places her lips around the areola (the circular area of pigmented skin surrounding the nipple) and squeezes the nipple between her tongue and palate. (Called “expression,” this action forces out the milk.) Then comes the second phase, or the milking action, in which the tongue moves from the areola to the nipple. This whole process is helped by the negative pressure, or suction, that secures the breast in the baby’s mouth.

Coordinating these rhythmic sucking movements with breathing and swallowing is a relatively complicated task for a newborn. So even though this is a reflexive action, not all babies suck efficiently at first. With practice, however, the reflex becomes a skill that they all manage well.

As rooting, sucking, and bringing her hand to her mouth become less reflexive and more directed, your infant will start to use these movements to console herself. She also may be comforted when you give her a pacifier or when you help her find her thumb or her fingers.

Another, more dramatic reflex during these first few weeks is called the Moro reflex. If your baby’s head shifts positions abruptly or falls backward, or she is startled by something loud or abrupt, she will react by throwing out her arms and legs and extending her neck, then rapidly bringing her arms together and she may cry loudly. The Moro reflex, which may be present in varying degrees in different babies, peaks during the first month and then disappears after two months.

One of the more interesting automatic responses is the tonic neck reflex, otherwise known as the fencing posture. You may notice that when your baby’s head turns to one side, her arm on that side will straighten, with the opposite arm bent as if she’s fencing. Do not be surprised if you don’t see this response, however. It is subtle, and if your baby is disturbed or crying, she may not perform it. It disappears at five to seven months of age.

You’ll see still another reflex when you stroke the palm of your baby’s hand and watch her immediately grip your finger. Or stroke the sole of her foot, and watch it flex as the toes curl tightly. In the first few days after birth, your baby’s grasp will be so strong that it may seem she can hold her own weight—but don’t try it. She has no control over this response and may let go suddenly.

Aside from her strength, your baby’s other special talent is stepping. She can’t support her own weight, of course, but if you hold her under the arms (being careful to support her head, as well) and let her soles touch a flat surface, she’ll place one foot in front of the other and “walk.” This reflex will disappear after two months, then recur as the learned voluntary behavior of walking toward the end of the first year.

Although you may think of babies as utterly defenseless, they actually have several protective reflexes. For instance, if an object comes straight toward her, she’ll turn her head and try to squirm out of its way. (Amazingly, if the object is on a path that would make it a near miss instead of a collision, she will calmly watch it approach without flinching.) Yes, she’s very dependent on her mother and father at this age, but she’s not totally defenseless.  

Newborn Reflexes

The following are some of the normal inborn reflexes you will see your baby perform during her first weeks. Not all infants acquire and lose these reflexes at exactly the same time, but this table will give you a general idea of what to expect.