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Age: 7 to 9 months

Babies often become mobile at age 7 to 9 months.

​Understanding your child's changing and emerging growth and development is an important part of parenting.

The following guidelines will help you monitor your child’s development. 

It’s important to note that not all children develop at the same rate, so comparing your 18-month old son to your neighbor’s 18-month old daughter may not be the best method.

These guidelines will help you spot potential problems and alert your Marshfield Clinic pediatrician. 

Your child’s doctor can determine if there's a problem or not. 

The Growing Child: 7 to 9 Months

7 to 9 month old baby crawling.

How much will my baby grow?

While all babies may grow at a different rate, the following indicates the average for boys and girls 7 to 9 months of age:

  • Weight: average gain of 1 pound each month; boys usually weigh about ½ pound more than girls; 2 times the birthweight by 4 to 5 months and 3 times the birthweight by 1 year

  • Height: average growth of about ½ inch each month

  • Head size: average growth of about ¼ inch each month

What can my baby do at this age?

Babies are rapidly developing their physical abilities at this age. They become mobile for the first time and safety in the home becomes an important issue. While babies may progress at different rates, the following are some of the common milestones your baby may reach in this age group:

  • Rolls over easily from front to back and back to front

  • Sits leaning forward on hands at first, then unsupported

  • Bounces when supported to stand

  • Gets on hands and feet and rocks back and forth

  • May creep, scoot, crawl--backward first, then forward

  • Begins to pull up to stand

  • Reaches for and grasps objects using whole hand

  • Bangs toy on table

  • Can hold an object in each hand

  • May hold a bottle

  • Plays peek-a-boo

  • Grasps object with thumb and finger by 8 to 9 months

  • Begins teething, usually starting with the 2 center front teeth in the lower jaw, then the 2 center front teeth in the upper jaw

  • Learns to drink from cup

  • Puts everything into mouth

  • Naps are usually twice, sometimes 3 times a day, for 1 to 2 hours each (on average)

  • May begin to awaken during the night and cry

What can my baby say?

It is very exciting for parents to watch their babies become social beings that can interact with others. While every baby develops speech at his or her own rate, the following are some of the common milestones in this age group:

  • Makes 2 syllable sounds (ma-ma, da-da)

  • Makes several different vowel sounds, especially "o" and "u"

  • Repeats tones or sounds made by others

What does my baby understand?

A baby's awareness of people and surroundings increases during this time. While babies may progress at different rates, the following are some of the common milestones in this age group:

  • Responds to own name and "no"

  • Pays attention to conversation

  • Appears to understand some words (such as "eat")

  • Prefers mother over others

  • Enjoys seeing self in mirror

  • Responds to changes in emotions of others

  • Is afraid of strangers

  • Shows interest in and dislike of foods

  • Makes attention-getting sounds, such as a cough or snort

  • Begins to understand object permanence and can uncover a toy after seeing it covered

  • May follow one-step commands with a sign to demonstrate (such as, "get the ball" while parent points to ball)

How to help increase your baby's development and emotional security

Consider the following as ways to foster the emotional security of your baby:

  • Give your baby safe toys that make noises when shaken or hit.

  • Play in front of a mirror, calling your baby by name and pointing to your baby's reflection in the mirror.

  • When talking to your baby, pause and wait for him or her to respond just as when talking with an adult.

  • Play pat-a-cake and peek-a-boo.

  • Name common objects when shown to your baby.

  • Make a variety of sounds with your mouth and tone of voice.

  • Repeat and expand the sounds your baby makes, such as "ma-ma" when he or she says "ma."

  • Show picture books and read stories to your baby every day.

  • Give your baby toys with objects or knobs to push, poke, or turn.

  • Give your baby toys that stack or nest and show him or her how they work.

  • Build a tower with your baby and show him or her how to knock it down.

  • Establish a routine for bath and bedtime.

  • Offer a cup.

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Call: 1-866-520-2510

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What Do You Know About Child Development?

Test your knowledge of child development by taking this quiz.

1. When riding in a motor vehicle, how tall should a child be to sit in a regular seat and use an adult seat belt instead of a being strapped into a car safety seat or booster seat?
2. For which of these should you call your doctor instead of trying at-home treatment?
3. Two out of 3 teen girls don't get enough of which of these in their diet?
4. How much has the rate of obesity in children increased in the last 35 years?
5. Menstruation can begin at which of these ages in girls?
6. It's estimated that 3 to 7 percent of American school children have attention deficit hyperactivity disorder (ADHD). Which of these famous people is thought to have had the condition?