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Your newborn will grow very quickly during his or her first few months of life.

He or she may have lost about 10% of their birth weight in the first few days after birth, but worry not as they should gain it back by 2 weeks.

Although all babies grow at different rates, the list below contains some average measurements and growth rates for babies up to 1 month of age.

  • Weight: after the first 2 weeks, your newborn should gain about 1 ounce each day.
  • Average length at birth: 20 inches for boys, 19 ¾ inches for girls.
  • Average length at 1 month: 21 ½ inches for boys and 21 inches for girls.
  • Head size: will grow slightly less than 1 inch by end of the first month.

Newborn Reflexes

Many of a newborn’s movements and activities are reflexes. Reflexes are movements that a baby does not voluntarily make. When your baby’s nervous system matures, you will begin to see more purposeful behaviors and fewer reflexes.

The following are common reflexes in newborns:

  • Moro reflex (or startle reflex): When a baby is startled by a loud movement or sound, they will throw back their head, throw out their arms and legs, cry and pull their arms and legs back in. Sometimes a baby’s own cries can startle them. The Moro reflex lasts until your baby is around 5 to 6 months old.
  • Root reflex: Something touches the corner of your baby’s mouth they will turn their head and open their mouth in its direction. This reflex, known as rooting, helps babies find a breast or bottle near their mouth.
  • Suck reflex: A breast or bottle nipple touches the roof of a baby’s mouth and they begin to suck. As this reflex is not fully developed until about 36 weeks of pregnancy, premature babies may have weak or immature sucking ability. Babies also have a hand-to-mouth reflex. This accompanies rooting and sucking and babies will often suck on their fingers or hands.
  • Tonic neck reflex: A baby assumes a “fencing” position when lying down. If a baby’s head is turned to one side, the arm on that side stretches out and the opposite arm bends up at the elbow. This is common until the baby is about 6 to 7 months old.
  • Step reflex: When a baby is held upright with their feet touching a solid surface, they appear to dance or take steps, bouncing their feet up and down.
  • Babinski reflex: When the sole of a baby’s foot is rubbed, the big toe bends back toward the top of the foot and the other toes fan out. This reflex continues until a child is about 2 years old.
  • Grasp reflex: If you stroke your baby’s palm, your baby will close his or her fingers in a grasp. This reflex is stronger in premature babies and lasts only a couple of months.

Newborn Behaviors

In addition to reflexes, newborns also have behaviors and physical characteristics that are common, including:

  • Occasional appearance of crossed eyes
  • Head sagging when the baby is lifted without his or her head being supported
  • Erratic, jerky movements
  • Lifting their head when lying on their stomach
  • Moving their hand to their mouth
  • Fixing their eyes on light or a face and then following the moving object with their eyes
  • Turning their head from side to side when lying on their stomach

Newborn Responses

A newborn’s main form of communication and response is crying. After some time, parents are able to recognize different types of cries for discomfort, hunger, fatigue, frustration and even loneliness. However, a newborn’s cries may also be unpredictable and mysterious, ending as quickly as they begin without a discernible reason. No matter the cause of the crying, when you respond to your baby with comfort, they will learn to trust and look to you for security. This is an essential time for parent and child bonding.

Your baby may also respond to you in other ways, such as:

  • Smiling, especially during sleep
  • Turning in the direction of sounds or voices
  • Looking at faces and pictures with high contrast
  • Startling at loud noises

Emotional Security and Development

Newborns thrive in the comfort and security of their parents’ presence. They are reactive to your tone of voice, emotions and mood. The following list offers ways to encourage emotional security in your newborn:

  • Speak to your baby in an affectionate, warm and soothing tone of voice.
  • Sing to your baby.
  • Walk with your baby in a stroller or carrier.
  • Hold your baby close to your face or against your skin.
  • Swaddle your baby to help them feel secure and prevent the startling reflex.
  • Respond promptly to your baby’s cries.
  • Rock your baby gently.

Emily Bendlin, MD

Methodist Physicians Clinic - Hawthorne Court

Dr. Bendlin loves working with kids and their parents. She has always enjoyed caring for kids.  "I've always liked medicine, but more importantly I've always liked kids," Dr. Bendlin said. "During my pediatric rotation it was the 'aha' moment. It was so fun and I was so excited when I went home. I knew at that time this is it for me – pediatrics is where I’m supposed to be." According to Dr. Bendlin, "Working with kids is fun. What other ...

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