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Your 42-week-old Baby – Development & Growth

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42-week-old baby

Table of Contents

How is your baby forty-two weeks after birth? You can expect a 42nd-weeker to start being a great problem solver at this young age. This also means they will try to reach their favorite toy that is kept away or far off their reach. They will push towards it or try to reach or cry out to someone around until they get what they need. But the good news? Your baby is all ready to build on their cognitive skills at 42 weeks.

It’s not all goody good too because they will have separation anxiety and may lose their sleep over it. You may have to spend more time comforting and consoling them during the night.

Also, be prepared to find chewed boxes and paper all around the floor as your 42 weeks old baby begins to move, crawl, and run all around the house, much more confidently.

Read on to know more about what you may expect from the little one!

Your 42-week-old Baby's Major Changes

Let us now understand what happens with the little one in the 42-week after birth in terms of the baby’s development in the forty-two-week.

Your Baby’s Weight

Expect your baby to weigh anything from 18.11 lbs to 20.3 lbs. Nonetheless, if you observe the weight to be more or less, contact your doctor to be on the safer end.

Your Baby’s Sleep

42 weekers crawl more than they walk which increases the baby’s activity. It also influences their ability to regulate their movement. This means they stay more awake at night.

We understand it won’t be easy to see your baby in pain, but do understand that it is a part of their development to enhance their teething and mobility. Teethers can also help your baby ease their discomfort.

You could sing your little one to sleep and/or give them a little piece of cold food like a baby-sized watermelon. However, before you do anything new or if the baby doesn’t seem to be sleeping better, consult your doctor immediately.

Your Baby’s Diet

The eating patterns might change this week as the 42-week-old baby happens to change its feeding behaviors. This could be due to them adjusting to solid food with breast milk. Expect the baby to skip a meal a day or two and do not worry as the breast milk takes care of the nutrition otherwise.

A baby might also not need a bottle and may use a sippy cup instead. So, in case you are away, make sure to store your breastmilk for the caregiver to give.

What to Do at a Clinic With Your 42-weeks-old?

A 42-week-old baby or ten months old is acquiring major milestones and visiting the doctor for a check-up counts as one. Here’s what you can expect from the visit to the baby’s doctor:


Expect the doctor to check the baby’s height and weight to track the baby’s growth and development.

Blood test

The doctor may also opt for a blood test for the baby to check the levels of iron, hemoglobin, or anemia in the baby.


Be prepared for the baby (still to complete the first year) to get the following vaccines anytime between 6-18 months:

  • Final shot for the Hepatitis B vaccine
  • A dose of the influenza vaccine
  • A third dose of the IPV (polio) vaccine

Development in a 42-week-old Baby

Brain Development in a 42-week-old Baby

At 42 weeks or 10 months, expect the baby to start grasping concepts like time, distance, depth, cause, and effect that they will intend to incorporate while playing. For instance, they will be able to knock the cones placed at a distance, could arrange different sizes of rings in a plastic stand, separate different colors, etc.

They will still be excited and will be able to grasp certain properties of objects by crumpling, ripping, tasting, and throwing, which in return increases their dexterous hands. The baby might be able to project different emotions, ranging from laughter to sad to sleep-like.

The little one might also be able to smack their lips and murmur or stamp their feet while listening to their favorite music piece, or even dance as per their choice and mood.

Physical Development in a 42-week-old Baby

Here is what you can expect from a 42-weeker in terms of their physical development:

  • They will be able to get into a sitting position from lying on their stomach
  • Will learn to walk fast while holding onto some furniture. So make sure to place some cushions in a hurt-prone area
  • Will understand a ‘NO’ from you
  • The baby will be able to clap and wave at you
  • Can bend while standing or even pinch objects between their tiny fingers
  • Can roll around on the floor. So, try to place playmats instead.
  • Will be able to understand instructions like ‘come to mama’ when accompanied by gestures
  • Your baby will be able to solve their problem
  • The need for games for your baby to build motor skills
  • Play games with your baby that involve simple instructions. For example, place a teddy somewhere around and ask the little one, ‘Where’s your teddy?’ This helps enhance the problem-solving skills of your baby.
  • Play games like putting the toys back in the box. This game will encourage them to understand the need of keeping the place clean.
  • Sit across and ask your baby to come to you. This is the best way to help develop motor skills.

Postpartum Baby Tips at Week 42 After Birth

Your baby at 42 weeks is already acquiring and achieving major physical and cognitive skills. Therefore, here are a few tips and things that parents must be aware of during this week to be well-prepared for advice.

Here are a few tips for our parents to help them simplify their journey with their 42nd-week-old baby:

  • Understanding basic care routines for your baby
  • Use baby soaps and shampoos to avoid irritation and a chemical reaction
  • Avoid using any clips and bands for the baby as they could cause choking hazards in your baby. Instead, use baby headbands as they are made from materials that are safe for the babies.
  • Use a baby nail clipper when the baby is asleep to avoid any scratches and dirt.
  • Use a sippy cup that is easy-to-hold
  • Understanding your baby’s health and the urgent need for a doctor

Listed below are a few instances where parents must consult a doctor regarding their 42-week-old baby during this week:

  • Contact your doctor if the baby experienced an insect sting or a bite as it can be harmful to the baby’s health if it stays red and your baby experiences fever.
  • Also remember, if you notice a sting on your baby, remove it by scraping it, and also wash the area with water and soap, and then apply an ice pack or baking soda to relieve the pain.
  • If your baby has trouble breathing, is wheezing, has a rash, experiencing swelling on the tongue, hands, or face, you could need to consult a doctor as it might be due to an allergic reaction or an anaphylactic shock.

A Final Word

Your baby in the 42nd week is becoming a more active and responsible child in terms of its growth and development. However, you can expect yourself to run around and feel more like a parent now as compared to before, as the little one would now like to move around from one place to the other at a better speed and would perhaps be messing their play area.

Your 42-week-old baby FAQs:

1. What should a 42-week old baby eat?

A 42-week old baby is at present adjusting to solids with breastmilk. Therefore, you can expect the baby to adjust and fill with solids a day and refuse to consume them on the others.

2. How many months are a 42-week-old baby?

A baby at 42 weeks is nine and a half months. Expect the baby to be able to learn new words, respond quicker, walk faster while holding things, and develop different gestures like waving to you.

3. What can a baby at 42 weeks do?

At 42 weeks a baby can sit confidently, walk faster, stand without support, and be able to bend while standing.

On behalf of the editorial team at Parenthoodbliss, we follow strict reporting guidelines and only use credible sources, along with peer-reviewed studies, academic research institutions, and highly respected health organizations. To learn about how we maintain content accurate and up-to-date by reading our medical review and editorial policy.

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