3 Week Old Baby’s Development Guide For Parents


Taking care of your 3-week old baby can be quite a challenge. Your little one will become more active as well as alert during this period. You can even notice that your baby is behaving completely different from just a few days ago. Welcome to the rocky but wonderful world of being a mother!

Some things you got used to are not going to work anymore. This is a natural part of your little one’s development because the changes happening at this stage can be pretty significant. That is why it is important to understand how to handle baby development 3 weeks after birth.

What You Need to Know

  • Remember to take a break now and then
  • Keep looking after yourself as well
  • Your baby should get enough vitamin D

You should always remember to take a break during this stage of your baby’s development. Taking care of a 3-week old baby can be exhausting. Your child is likely to become more alert and active at this time, as well as more irritable, experiencing more tears and fussiness.

That is why it is crucial to make a plan for relaxation and give yourself a break whenever you feel overwhelmed. In case you need some time to clear your mind or release the tension, you could put your little one in a safe place and walk away for a few minutes.

You should also continue the process of self-care after giving birth. At this stage, you are probably feeling a bit stronger but that does not mean your body can function properly without enough nutrients and rest. You need to heal properly, so make sure to drink enough water and take your vitamins which will help you stay nourished.

It is important to remember that you should give your baby appropriate vitamin D supplements in case you are breastfeeding since vitamin D is not found in breast milk. However, do not use any medication before consulting your doctor. They will advise you on the adequate dosage which you can simply get at the store. There is no need for any supplements if you are using a formula to feed your baby since it already contains enough vitamin D.

Your Baby is Growing

You will notice a rapid growth in your 3-week old baby. It will be gaining 2/3 oz (20-30 grams) every day, resulting in putting on roughly 1.5-2 inches (4.5-5 centimeters) by the end of its first month.

In case you are curious, the average male baby has a head circumference of 15.4 inches (39.21 centimeters), while the average female baby has a head circumference of 14.9 inches (37.97 centimeters).

Milestones in Your Baby’s Development

Baby development 3 weeks after birth will be noticeable every single day. Your little one is now able to lift its head and will even start turning it from side to side, following you as you are moving around the room. It will be trying to give you its first smile during this period, copying your movements while sticking its tongue out. You might also notice your baby is making different sounds, which is a great sign of proper development.

Your baby might seem like it is carefully listening to what you are saying or studying your face or your moves. Even though a 3-week old baby is not going to understand your words, you should try to speak out loud as much as possible. Even at this early stage, this can be beneficial for language development so do not miss any chances to speak. Reading a baby book can be one of the options.

Since your baby is growing, you will notice more tears or fussiness, especially at night or in the evening. This should not worry you because it is a normal part of the development. Also, you can notice the symptoms of colic during this stage as well. They can be frustrating and exhausting for both you and your little one. Here are some tips which could help you get through these ‘’growing pains’’:

  • Start doing a relaxing evening routine: Bathing your little one, followed by a gentle massage with baby lotion can be a great option for your evening routine. In case your baby is experiencing tummy problems, you could also try giving a special massage which helps relieve excessive gas.
  • Avoid using gripe water: Even though some doctors recommend using gripe water to treat irritability and gas, recent studies have shown that this remedy might not be the most effective.
  • Take care of your diet: Certain types of food can be upsetting your little one’s stomach so you should pay attention to your diet. If you notice that your baby gets particularly fussy after it is fed, or it is gassy, it might help if you keep track of your food intake. Certain food such as caffeine, seeded fruit (raspberries for example), or chocolate can cause your baby to experience digestive problems.
  • Place your little one in a safe spot: You need to relax now and then so you can properly function and take good care of your 3-week old baby. No need to push yourself over your limits if your baby has been changed, fed, and played with. If you are not feeling well, simply take a break. Take a few deep breaths while your little one is safely placed in its crib. Taking care of baby development 3 weeks after birth is quite a challenge, especially if your little one is experiencing symptoms of colic. You should not feel bad for wanting to take a break because every parent needs it.

When You Should be Concerned

At this stage, it might be a bit difficult to realize whether your little one’s fussiness is a normal part of its development, or there is something more to it. You should seek immediate medical attention in case your baby is refusing to eat, is not gaining weight, is projectile vomiting, is experiencing excessive spit-up, or has blood in its stools. Doctors will give you the best possible advice when it comes to taking care of your baby or treating any conditions.

Babies usually develop colic around week 3, so you could follow your baby’s crying pattern to determine whether there is anything abnormal about it. If a baby has colic, it tends to have periods of crying which last two or three hours a day, usually happening at night. There is not a definite cause of colic but it is a normal thing for most babies, affecting up to 40% of children. It is strongly advised to take your little one to a doctor to get the best possible advice on the treatment.

Your Regular Day

Your 3-week old baby should have a daily routine which includes regular massaging. There is no need to make a strict schedule. You could use a few minutes when your baby is not busy with anything else to introduce tummy massages. Do not get discouraged if your baby does not completely enjoy it at first because small steps every day will take you there. Regular tummy time is important to encourage baby development 3 weeks after birth, strengthening its neck muscles.

You should keep it simple and place your baby on a blanket or a nursery rug on the floor. Also, you could use your breastfeeding pillow. Make sure you always stay by your baby and you never leave it without supervision.

In case this is your first baby, you might get a bit confused when it comes to taking care of it. Talking to your little one and changing its diapers is not everything that should be done during this stage. This is a great time to start introducing new activities, such as:

  • Using a stroller to go out for a walk with your little one
  • Introducing your baby with some toys, such as baby mobiles or play mats
  • Going outside together using a baby carrier or car seat

Basics of Baby Care

You can continue cleaning your baby’s penis with mild soap and water in case it was circumcised at birth. The wound should be healed by 3 weeks old so contact your doctor in case you notice any changes such as pus, redness, or drainage.

If your baby is uncircumcised or it has foreskin left on its penis, you should not force it down. The foreskin will naturally retract by the age of 5, or longer in some cases. You should clean the head of the penis like you would clean any other body part until then.

If you have a baby girl, there might be some vaginal discharge which you can notice during bath time or diaper changes. It can appear white, clear, or even blood-tinged. Even though it can seem alarming, there is no reason to worry because this is a normal part of the development.

Delivery, breast milk production, as well as mother’s hormones during pregnancy can be the cause of vaginal discharge. In case you notice that it lasts for a long period, you should consult your baby doctor.

Your hormones can also cause some other changes. For example, your baby’s breasts can appear enlarged during the first few days after birth. However, the swelling should go down by week 3.

At this stage of its development, your baby is likely to develop lacrimal duct obstruction or a blocked tear duct. Some parents do not realize that this is happening until they see green or watery drainage near their little one’s eye.

This condition is common and the symptoms will go away on their own by the time your baby becomes one year old. However, you should be careful because your little one’s tear ducts can become infected. Applying a warm washcloth compress can help clear its tear duct and provide relief.

Your baby can also be experiencing certain skin problems at 3 weeks old. For example, it might develop baby acne (this does not only happen to teenagers), rashes, or cradle cap which look like ‘’scales’’ on your little one’s scalp. Skin irritations during this time are usually harmless and normal, but there are some things you can do to make your baby feel more comfortable:

  • Do not use harsh soaps or shampoos
  • You could reduce bathing time to only once or twice a week
  • Use baby-safe fabric softeners and detergents which are gentle
  • Avoid using anything which could cause irritation
  • Keep track of your baby’s symptoms whenever you change a skincare product
  • Never squeeze or pop your little one’s blemishes because they will go away on their own
  • Try using a gentle baby brush to loosen the scales while you are bathing your child
  • If your little one is experiencing diaper or heat rash, let it go without diapers or clothes for up to two hours inside the house

Nutrition and Feeding


Around this time, you can introduce a pacifier if your little one feels comfortable about it. However, some doctors are not in favor of using pacifiers early on before the mother’s milk supply is established to prevent nipple confusion.

On the other hand, The American Academy of Pediatrics recommends using pacifiers because certain studies point to their benefits. For example, using pacifiers is believed to be associated with a lower risk of SIDS (Sudden Infant Death Syndrome). Deciding whether or not to introduce a pacifier is a personal choice after all. Remember to never force it because some babies might not be comfortable with it.

Baby development 3 weeks after birth will not be as fast compared to week 1 and 2. You can also notice a small decrease when it comes to feeding frequency. This decrease is perfectly normal because your baby experienced a growth spurt in the previous weeks. During this time, you should feed your little one on-demand with nursing sessions lasting from 20 minutes to an hour.

It is important to continue providing your baby with its daily vitamin D supplement in case you are breastfeeding. Your hospital should provide you with free vitamin D drops. However, if that is not the case, you should contact your doctor to see what can be done about it.

Breast milk is not a good natural source of vitamin D. That is why supplements are important for your newborn. Any vitamin deficiency can cause further complications, especially now when your little one’s bones continue to grow.

It is a good idea to think about pumping by this time. A supply of frozen breast milk can significantly help you in nursing. This can be a great option if you are coming back to work or you simply want to have more feeding options. If you decide to go for it, do it after feeding your little one and after you make sure they are full.

The beginning and the end of a feeding session contain completely different types of milk. Hindmilk is a type of milk that can be found toward the end of a feed. It contains more fat which is good for the baby so it is important it completely empties your breast before you start pumping.

If this method does not work for you, you could try pumping during the day. For example, you could do it in the early afternoon when your little one is napping. When you are done, place your milk in a freezer-safe container and do not forget to label it once it is stored.

Do not worry about overeating because it is very difficult for your baby to do so at this stage. If you feel like your little one is consuming more than you expected it would, do not be alarmed. If you are confused about giving formula to your baby, measure its weight and then feed it 5-6.5 oz per 2.2 pounds (150-200 ml per kilo). However, it would be ideal if you could feed your baby whenever it needs it because babies are typically aware of how much food they need at this time.

Monitoring how much your baby is eating can be a bit difficult if you are breastfeeding, but it should be alright as long as your little one is latching on.


Your 3-week old baby should be sleeping most of the time, around 16-18 hours per day. Creating a strict sleeping schedule is still not a good idea. However, you can try introducing some sleeping cues, such as reading or bath time. Your baby should lead the sleeping pattern on its own during its first few weeks of life.

Bowel Movement

Naturally, every baby is different so it will have different bowel movement patterns. Some do it right after a meal, while others do it less regularly. If it is happening between one and ten times a day, you have got nothing to worry about. However, it is a great idea to consult your doctor if you have any concerns.

Safety and Health

Your baby might enjoy swaddling to calm down or fall asleep. If you choose to do it regularly, you should be aware of the sleep guidelines proposed by the American Academy of Pediatrics. According to them, the risk of SIDS is high for babies who are swaddled and placed on their sides or stomachs afterward.

Your baby should be placed on its back after being swaddled to achieve maximum safety. The AAP also advises swaddling more loosely around the hips and more tightly around the chest area. This prevents worsening any case of hip dysplasia. According to the AAP, you should stop swaddling once your little one starts rolling. It is not supposed to be completely ready for this at this time but you should be careful during nap times.

In case your baby experienced jaundice in the past two weeks, all symptoms should be gone by now. Consult your pediatrician if your little one has yellowing of the eyes and skin, or if it seems lethargic.

Baby Planet Overview

Even though parenting a 3-week old baby can be challenging, it is lovely watching your little one change every day. You will most likely notice more movement as well as fussiness and might even think that your baby is completely different from the one you brought home. It will try to smile, follow your every move, or produce different sounds. This is a normal part of your baby’s development.

However, all those changes can be a bit difficult to handle. That is why it is very important to know what exactly should be done in terms of feeding, care, and sleep. If you are still having doubts, consult your doctor for the best possible advice. Enjoy your parenting days!

More Baby Reviews:


  1. What to Expect from a 3-Week-Old Baby, Livestrong
Hello Mother's and Father's of the world. My name is Sarah Nielsen is this is my passion MyBabiesPlanet.com, as I am a mother of two beautiful babies and they are my world. Also I love blogging and sharing my experiences of what has worked for me when raising my kids. When I'm not juggling the madness at home, or working on my blog. You will find me product researching and keeping the site freshly updated with the latest baby gear and helpful articles for my readers!