The Growing Child: 7 to 9 Months

How much will my baby grow?

While all babies may grow at a different rate, the following is 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. Generally, expect 2 times the birth weight by 4 to 5 months and 3 times the birth weight 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. Babies may progress at different rates. But these are some of the common milestones most babies reach in this age group:

  • Gets into a sitting position by themselves

  • Sits without support

  • Reaches for and grasps objects using fingers

  • Can move an object from one hand to another

  • Plays peek-a-boo

  • Starts teething, often starting with the two center front teeth in the lower jaw, then the two center front teeth in the upper jaw

  • Puts everything into mouth

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

  • May start to wake up during the night and cry

What can my baby say?

It is very exciting for parents to watch their babies become social beings who can interact with others. Every baby develops speech at their own rate. But these are some of the common milestones most babies reach in this age group:

  • Makes a lot of different sounds like "mamamama" and "babababa" (ma-ma, da-da)

  • Smiles or laughs when you play peek-a-boo

  • Lifts arms up to be picked up

What does my baby understand?

A baby's awareness of people and surroundings increases during this time. Babies may progress at different rates. But these are some of the common milestones most babies reach in this age group:

  • Looks for objects when out of sight

  • Bangs two things together

  • Is shy, clingy, or fearful around strangers

  • Shows several facial expressions, like happy, sad, angry, and surprised

  • Looks when you call their name

  • Reacts when you leave (looks, reaches for you, or cries)

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

Here are some ways to foster your baby's emotional security:

  • 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 them 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 different sounds with your mouth and tone of voice.

  • Repeat and expand the sounds your baby makes, such as "ma-ma" when they say "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 them how they work.

  • Build a tower with your baby and show them how to knock it down.

  • Create a routine for bath and bedtime.

  • Offer a cup.

Online Medical Reviewer: Dan Brennan MD
Online Medical Reviewer: Liora C Adler MD
Online Medical Reviewer: Stacey Wojcik MBA BSN RN
Date Last Reviewed: 8/1/2023
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