Baby development and milestones: your 3 week old

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What is your baby's progress this week?

As new parents, it might be difficult to get a decent night's rest when your precious 3 week old baby keeps crying. However, that's the only way your baby can communicate with you right now. You might feel exhausted and frustrated for now, but remember that your newborn won't stay small forever. Let's see what 3 week old baby development milestones are in store for your little one.

3 Week Old Baby Development

Physical Development

By the third week, your baby's skin should be peeling less and looking more plump, pink and clear. Don't worry if your baby still has cradle cap – that rough scaly dandruff-like skin on his scalp – because most of the time, it will go away on its own. It might look unsightly and uncomfortable, but it won't bother your newborn.

Your 3 week old baby would have also gained the weight he lost in his first week, and he should continue to gain weight at approximately 25 grams per day. 

As part of 3 week old baby development, his movements might be jerky and uncontrolled, which is normal for a newborn. This is because your baby's nervous system and muscle control still need time to mature. In time, when his muscles get stronger, his movements will become more and more fluid.

It is likely your baby will still be sleeping most of the time, just make sure to put him down on his back as that is the safest sleeping position. But during the short moments that he is awake, you can put him on his stomach to do some tummy time. This helps strengthen the neck muscles so they can push up to sit, roll over and crawl in the later months.

When to see a doctor

If your baby: 

  • Is still losing weight

Cognitive Development

3 week old baby development 2 Baby development and milestones: your 3 week old

At three weeks, your baby is still trying to adjust to being outside of your womb. Loud noises will still startle him, trigger the waterworks and his Moro reflex. To help him calm down and feel more secure, you can always try swaddling him. 

Another way for a baby to soothe themselves is by sucking.  However, if you are nursing, you might want to wait until breastfeeding is well established before offering a pacifier so they can self-soothe. Even if you don't offer a pacifier, sucking on his own fingers will also help your baby to self-soothe.

But did you know that you can also comfort your newborn by talking softly to him? Your little one can recognise songs or sounds he heard when he was still in your womb and mum's voice is one of the sounds he hears the most.

So continue to talk and sing to him, and even though he can't understand you yet, you are already laying the foundation for language development. 

Try hanging a mobile in high contrast colours or black and white over their cot. You'll see your baby gazing at the mobile or tracking it with his eyes. 

Now it might seem as though all your baby does is feed, poop, sleep and repeat. But his brain is actually absorbing a lot of new things during his 3 week old baby development phase. 

A good way to help him learn is to put your face in front of him during tummy time. Allow him to study your face and copy your lip movements. It might be very subtle, but if you watch him carefully enough you might actually notice him trying to copy you.

Right now, you baby's main mode of communicating with you is by crying. While it might be frustrating at first trying to distinguish the different types of cry -- hungry/ bored/ sleepy/ lonely/ over-stimulated, and so on -- soon, you'll be able to make those subtle differences. 

For now, try to rule out one cause at a time. Offer your breast, change their position so they see a "new view", gently rock them, change their diaper or clothes. Hang in there mummy, you got this! 

When to see a doctor

If your baby:

  • Does not startle at loud noises
  • Does not cry at all

Nutrition and Health

Breastfeeding should be well established by now, and your breasts might be full and heavy with milk. There is no hard and fast rule about when to nurse your baby. At this age, feeding on demand is still best. The best way is to take cues from them and feed whenever they need it, as babies typically know exactly how much food they need.

As long as your baby is latching well, satisfied and gaining weight, then all is well. Check for lip and tongue ties if you have facing breastfeeding problems. You will still be able to breastfeed if your baby has a cleft lip or palate.

Also, remember to let baby drain each breast at each feed so you don't suffer from blocked ducts or mastitis. 

If your baby was already having colic problems before this, then it might probably still be there during his 3 week old development phase. While it might be heartbreaking to see your little one so uncomfortable, this too will also pass. However, if it seems to be getting worse, his paediatrician might be able to offer some relief. 

This week, there are no vaccinations due for your baby.  However remember that next week as your baby turns one month old, he'll be due for the second dose of the Hepatitis B vaccine. To find out more about your baby's vaccination schedules, please click here

When to see a doctor

If your baby:

  • Seems to have trouble breathing, indicated by rapid breathing, flaring of the nose, grunting while breathing or bluish skin that refuses to fade. 
  • Vomits constantly.
  • Has white patches on his tongue, which could indicate oral thrush.
  • Has even a slight fever (over 37 degrees Celsius). 
  • Has trouble latching on to your breasts. 
  • Has a bloated, highly distended stomach.

Newborn Care

3 week old baby development 3 Baby development and milestones: your 3 week old

Make sure you do not shake your baby especially when they won't stop crying. Your baby's neck is still very weak and cannot fully support his head. Shaking can cause your baby’s fragile brain to slide back and forth within his skull, possibly inflicting irreversible brain trauma also known as shaken baby syndrome.

Ensure that the room your newborn is sleeping in is of the right temperature. The ideal room temperature is 24ºC if you are using an air conditioner. At this temperature, their body is not fighting to stay cool or trying to warm up.

At three weeks, your little one will still be sleeping a lot, regardless of day/night. But, it's not too early to gently start teaching them about the difference between day and night. 

Try introducing a bedtime routine: bath, nurse, cuddle and sing/talk at the same time every evening. Do your last feed in a dark room with dimmed lights. With night-time feeds too, keep the lights dim and try to engage your baby too much as you would in the daytime. Don't expect changes to happen overnight, but over the months, your little one should start associating the bed-time routine with sleep. 

Continue to bathe your baby carefully, supporting his neck and back to prevent slipping. If you have a son, click here to read about how you should clean his genitals, and if you have a baby girl, here's your article

Remember that you should never insert cotton buds (or anything else) in your baby's ears to clean them. This could rupture baby's ear drum or push the wax in further, creating health issues. 

When to see a doctor: 

  • If you notice any discharge from your baby's genitals
  • If you or another caregiver accidentally drop your baby

New Parent Wellness

If you can get extra help around the house, take it because chances are you will be tired and sleep-deprived. Nap when your baby naps. You can always live with a bit of mess at home as long as you get sufficient rest. Mums, please don't ignore the signs of postnatal depression. If you experience any signs, see your doctor without delay.  

Even if it is difficult going through your 3 week old baby development and milestones, remember that they don't always stay that small and dependent on you forever. Like many parents before you, you will pull through as well.

Enjoy this epic journey of getting to know your little one and create new memories one day at a time. Someday you will look back and remember that it was well worth it.

Source: Better Health Channel, Seattle Children's Organization

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