Your 40-week-old Baby – Development, Milestones & Care

your 40 week old baby - development, milestones and care

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Growing up is hard work for a baby! Every week will show a new skill he is trying to master, a new developmental phase he is going through, and a new issue he is dealing with. At 40 weeks, your baby will be preoccupied with the increasing number of teeth ready to blossom underneath his gums, and his drive to move around will increase day by day. He will also be more prone to mood swings and disturbed sleep, so this is time for proper care and nurturing.

Your 40-week-old Baby’s Development

At 40 weeks, your baby will be just about developing his personality. He may be quite social, smiling at everyone and he also may be shy, hiding his face when someone new comes along and tries to engage with him. Babies will start to assess situations before accepting someone new in their life when they are 10 months old. This can also result in quick and drastic switches of moods. They will gesture to get your attention and may even wave goodbye when you indicate that you are leaving the house. This is the age when your baby may even be able to stand alone on his own.

[Also Read: 9 Months Old Baby Growth and Development]

Your 40-week-old Baby’s Developmental Milestones

Below are a few milestones you can see in the development of your 40-week-old baby:

  • Your baby will be able to roll back a ball you roll towards him
  • Your baby will be able to stand alone for a short period of time
  • Your baby will be comfortable saying ‘mama’ or ‘papa’
  • Your baby will say one or two more words other than ‘mama’ or ‘papa’
  • Your baby will be able to pick up small objects between his forefinger and thumb
  • Your baby will be able to drink on his own from a cup
  • Your baby will be able to respond to any one-step comment you give him, along with hand gestures like, “give that to me” with your hand stretched out.
  • Your baby will be able to stand alone quite well
  • Your baby will learn how to sit back down from a standing position. His brain will slowly work out how to do the squatting movements to get up and sit back down

[Also Read: 9 Months Old Baby Milestones]

your baby will be able to stand alone quite well


Water bottles become highly attractive for babies at 40 weeks old – because of the water in them, and because of the way they roll around. Your baby will watch you drink and try to imitate you. If he spends a lot of time around other babies, you might have to constantly retrieve sippy cups that do not belong to him from his hands. 40 weeks is a good age to introduce drinking from a cup in your baby’s life. While he will get most of his hydration from breastfeeding, using his interest in water bottles to teach him to drink from a cup will be highly useful in preparing your baby for weaning. It is always better to let your baby drink water or milk from a cup. Juice is high in sugar and can cause dental problems or obesity, so help your baby get into the habit of drinking only water and milk from his cup even after weaning. Encourage your baby to drink a cup of water with each meal, to also let him know that water can quench thirst. Keep a sippy cup around your baby all day so he can drink water whenever he wants.

[Also Read: 9 Months Old Baby Food]


Your 40-week-old baby will experience sleep disruption at this stage due to a lot of different and simultaneous developments. His four top teeth will grow underneath his gums and will cause him discomfort. Along with the mental and mobility development he will experience, this pain will be enough to disrupt his sleep and keep him awake at night. Since he will not be able to sleep well at night, you will see your baby be grumpier and clingy during the day. Eating solid food or sucking from the breast might start to hurt, courtesy his swollen gums, leading to more frustration. Once his teeth erupt in his mouth, only then will he experience some relief. Till then, your baby might need you to feed, hold or carry him until he can forget the discomfort and go to sleep. Babies usually cling most to their mothers during this stage and refuse to go to anyone else. So be patient and do what you can to help your baby get through this painful teething stage.

[Also Read: 9 Months Old Baby Sleep Basics]

this is a good time to introduce your child to sippy cups

Care Tips for Your 40-week-old Baby

Here are a few ways you can take care of your 40-week-old baby:

  • Babies deal with separation anxiety at this age. Try not to sneak away when your baby is not paying attention. Let him see you go, wave goodbye and say you’ll be back. This will let him understand you are coming back.
  • If you leave your baby with a sitter, make sure that person has enough games and activities so your baby doesn’t experience sadness when you are away.
  • If your baby looks at something, look at it too, point it out and describe it. This will teach him to ask ‘what is that’ about something, knowing that you will give him the answer.
  • It is common at 40 weeks for babies to wake up suddenly and pull themselves up to cruise around the crib. Gently lay your baby back down, pat him on the back and encourage him to go back to sleep.
  • If your baby has not had a good night’s sleep due to teething discomfort or extra energy, put him down for a long daytime nap the next day.
  • Encourage your baby to try out his physical abilities by giving him a lot of floor space to walk and cruise along furniture. This will develop his muscles.
  • Babies will be prone to falling or bumping into things when they try walking so keep a first aid kit with bandages, gauze, tweezers and ointment on hand always.
  • If your baby starts to act out, put him in a safe place like a playpen or crib so that he doesn’t injure himself. Avoid always resorting to picking him up.

give your baby ample space to walk and cruise along furniture

Tests and Vaccinations

There will be a physical exam when your baby is 40 weeks old which will be done by the doctor based on the individual needs of the baby.

1. Tests

The doctor can do a blood test to determine levels of iron, haemoglobin and lead in your baby’s blood so that you can rule out any possible presence anaemia in your baby.

2. Vaccinations

The doctor will give your baby a shot of the measles vaccine and the fifth dose of oral Polio drops if your baby has been getting the dosage regularly.

Games and Activities

Here are a few games you can play with your 40-week-old baby:

1. Peekaboo

This game can help your baby get over any separation anxiety. Hiding your face and showing it again helps them know you are physically present even if they can’t see you.

2. Clap Hands

Play a game of clapping your hands and encourage your baby to as well. This can help them coordinate his hand movements.

3. Eyes, Nose and Mouth

Play a game where you ask your baby to point out where his eyes, nose and mouth are. This can help him learn the names of different body parts.

4. Dance and Sing

As your baby will be able to walk now, you can further encourage his mobility by dancing and singing alongside him.

[Also Read: 9 Months Old Baby Games and Activities]

clap hands as a game for your child to help him coordinate his hand movements

When to Consult a Doctor

Here are times you need to consult your doctor regarding your 40-week-old infant’s development:

40 weeks is a challenging age for your baby, so it is important as a parent to never compare your baby with another, even if the other baby shows different developments at 40 weeks of age. Don’t let self-doubt creep in. Every baby is different.

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