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Your 3-Week-Old Baby – development & growth

Table of Contents

3-week-old baby

Table of Contents

Your 3rd week baby is set on their journey of spit-ups, putting you on your journey of not feeling disgusted with all the mess. How to deal with spits-ups, how much spitting up is considered normal, and how to take care of the baby while dealing with your renewed body?

Your baby's third week after birth

A newborn baby in their three weeks after birth begins to grow into full-formed infants as compared to the earlier precious-but-super-sleepy newborns. So, yes you will now be able to view the infant as you might have imagined them to be like in your thoughts before you saw the little one post-birth. All thanks to the 3-week old baby’s development and a good intake of food.

However, not everything comes free and easy. There are a lot of changes and milestones that are rushing towards you, the parents! Here is everything you need to know with regards to the development milestones and what you could expect from the 3-week old baby.

Your 3-week-old baby's development and physical growth

Let us look at what is happening with your baby and in their body in terms of their physical development in the third week after birth.

1. Your baby's weight:

  • You don’t need to compare your baby with your friend’s baby anymore as the infants will now begin to put on pounds and ounces, now that they are in the third week after birth as they now stack up to their own weight and height curve.
  • For a closer look, the baby’s doctor will make sure to follow the baby’s growing trend and development. A big jump, that is from the 20th percentile to the 80th percentile indicated that the baby is gaining too fast. However, on the other hand, a big dip would mean that the little one isn’t getting enough to eat.

2. Your baby's sleep:

  • A 3-week old baby up to 3 or 4 months would require about 14 to 17 hours of sleep in a 24 hour period. They tend to wake up every two to four hours to eat. This gives you a little more time for the bonding sessions.

3. Your baby's diet:

  • Newborn babies consume roughly 16 to 24 ounces of breast milk or formula in a 24-hour cycle.

Your newborn and 3-week-old baby's reflexes

Wondering about the changes in a 3-week old baby? Surely, the past two weeks must have been a delight, but this week has much more to offer to the baby as well as to the parents. To know what to expect, read the following points that talk of the strength of the little one.

  • The newborn baby is perhaps getting stronger as the day passes and you can also encourage them to flex their muscles when you put your baby on their tummy for a good amount of time. This will allow the baby to practice lifting the head. Some will be able to lift up to 45 degrees too, dependent on their practice. Tummy time will also help prevent head flattening
  • The baby may also be ready for more complex shapes now with the rapid improvement in vision, ability to focus, and concentration. So, get ready to mostly notice the baby stare at their favorite soft toys or the mobile when waved in front of the face.
  • In fact, the 3 weekers would indulge in crying more often as compared to the early two weeks after birth. Most doctors refer to this as colic.

Your newborn and 3-week-old baby's health

Like the second, the third would also not have any doctor appointments. But, you will need to take care of other things that make you follow. Here is what you could expect from the 3-week old baby:

  • Baby spitting-up

A baby in their first few weeks after birth is prone to spit up more often, perhaps, you need not worry way too much. These spitting-ups after food are quite normal irrespective of the portion of the meal and it would calm down in a month or two. You should consult your pediatrician if your baby spits after each feed and doesn’t seem to gain any weight.

  • Baby fever

As per the American Academy Of Pediatrics, the baby in their third week could have a mild fever, that is under 100.4 degrees Fahrenheit, and it is nothing to worry about. However, if all the degrees tend to increase above 100.4 degrees, you must contact your doctor for further guidance.

  • The poop of the baby

In babies who have been breastfed, their bowel movements would be mustard in color, loose, and at times seedy. On the other hand, the babies who have been fed by the formula will have soft and pale yellow stools or yellowish brown, light brown, and brownish-green.

  • Ensuring the safety of the crib

Your baby’s cribs must be of utmost safety and should meet the standards of the Consumer Product Safety Commission (CPSC) for the baby to sleep in for more than three hours in one go. This will make sure your baby is well developed and strong. Also, to make sure that the baby’s needs are met, use the base baby crib mattresses too.

  • Vitamin D and the 3-week old baby

Baby needs up to 400 IUs of vitamin D per day. Therefore, if breastfeeding, the doctor will provide you with vitamin D drops for the intake. However, in case you feed the baby formula milk, it is already supplemented with vitamin D, so consulting the doctor with the drops would be required.

Postpartum baby tips: Week 3 after birth

You may notice a lot of changes in your 3 weeks baby and might have many ifs and buts that spin around in your head. This may include, what to give your baby; breastmilk or processed milk, what’s the baby’s skin like, how is the baby’s growth, etc. Therefore, Parenthood bliss is here with the answers. So, read on to know more!

Soothing baby's skin

It is almost 3 weeks, your baby has no sign of smooth skin as compared to the older babies who have smooth complexions, why?

  • As a sign of the baby’s immature circulation, the babies may look a little different with their skin being colorful but less-than-flawless, that is they have pink diaper rashes, flaky cradle caps, and purplish mottling. Consult your doctor for the next steps and ask if you could use a diaper rash cream instead to aid the pink rashes for soothing baby skin, that might be the reason for them crying aloud.
  • However, as parents, you must not get too worried as these imperfections in the baby’s skin are just temporary. These, like baby pimples and mottling, would go away on their own, and the assured clear baby skin is around the corner.

Newborn care during outings

Planning the newborn baby’s outing? Not yet, you must make sure of the below mentioned on a priority basis as this would be their first outing into the real world:

  • The first-month outing calls for more attention even though they seem to be developing really fast. These younger babies have quite a fatal immune system that is still to be strengthened. However, especially in the case of a prematurely born infant, or ones with other health concerns. In fact, if you could, try to avoid the putting until the second month till the baby develops a better immune system.
  • In case the outing is needed, try to avoid crowded areas, be it inside or out. Keep the babies in a baby stroller, sling, or carrier at all times.
  • When you get home, make sure to clean the baby’s hands with a soapy cloth, thoroughly to avoid any germs or infection.

Baby's cries, explained

Does your baby cry often or almost every day? Do you find yourself helpless? Why does a 3-week old baby cry more?

  • Most babies during the afternoon or early evening tend to cry more often. This could be a result of colic, or it’s a sign of the baby in pain. As per studies, the major reason for the baby to cry more is when they are gassy because they swallowed air when drinking formula that resulted in gas pain because of their immature digestive systems.
  • Easiest method to relieve a baby of gas is to make the baby lie on his or her stomach for a few minutes. This should typically NOT be done after a feed. And the other quickest method is to bring the legs of the baby to the stomach and release, do this about 5 times and the baby seems relieved.
  • You could also make use of pacifiers to calm the colicky babies.
  • This could be due to the baby’s tearful bouts and it could be a sign of overstimulation. This is important as the babies at this age might often need to unwind with a good cry at the end of a day.
  • Check the baby’s temperature using a baby thermometer to know if the baby is in fever. If yes, contact the doctor immediately.

The mother's body after childbirth: What is happening in your body in the third week after giving birth?

Fecal incontinence

Labor and delivery are noticed to be the toughest times, especially the mother’s body “down there.” This is due to the perineum muscles and nerves that stretch or get damaged, which makes it difficult to control how and when the food gets digested and passes through the body.

For this very reason, postpartum fecal incontinence is responsible to take care of it, as the body returns to normal. Perhaps, until that happens, here are a few steps that will help you to alleviate the cause:

  • Consume a gas-conscious diet, this means, skip hard-to-digest foods like anything fried, kidney beans, cabbage, or avoid overeating
  • Remember to do Kegels, as it helps in tightening up the muscles and the ones that are responsible to control urine
  • Do not shy away from talking about it to your doctor in case any problem persists. In such cases, the health care provider would suggest a possible mind-body technique, known as biofeedback, or possible surgery.

Breast Milk and Milk bank

There may be certain situations where a mother is not able to breastfeed their little one due to certain medical conditions, but your baby requires human milk. In cases like these, you can opt to get donated breast milk through a milk bank.

However, you must make sure of the following points before you begin your search:

  • As per the American Academy of Pediatrics (AAP) and other experts, you must avoid the casual breastfeeding of another’s babies even in cases of a friend. This is because there could be a certain virus or illnesses like Lyme disease or hepatitis that could pass through to your baby.
  • Unlike the informal arrangements, you could choose to feed milk to the baby from a milk bank in the U.S. as it has strict guidelines, as per the Human Milk Banking Association of North America (HMBANA). This would avoid any illness as the milk is checked and collected.

To Conclude

It goes without saying that the development milestones of a 3 weeks old baby are certainly quite a task for both the parents and the babies. So much so that, you may even feel this third week to be filled with certain ups and downs, considering the changes in both, the mother and the baby.  Perhaps, this week would require the parents to be wise and alert in nature.

There may be times where the baby would need medically reviewed attention, while the other would need a pure bonding session. Whatever it comes for you, parents must know that it’s hard to excel in being new parents and it would certainly take time to adjust to this newly formed parenthood. So, allow yourself to grow while the infant does too!

FAQs- Your 3-week-old baby - development and growth

1) Can a 3rd weeker baby have a growth spurt?

These spurts can generally occur anytime in the first year, however, it mostly makes its first appearance in between 1 and 3 weeks and the other between 6 and 8 weeks old.

2) How much should a 3-week old weigh?

On average, the weight of a newborn 3rd weeker is around 7 to 7 1/2 pounds, which is 3.2 to 3.4 kg. On the other hand, a full-term healthy newborns must weigh anywhere between 5 pounds 11 ounces to 8 pounds 6 ounces, that is 2.6 to 3.8 kg.

3) Does my 3-week old baby know who I am?

As compared to the earlier weeks the newborn is more alert in their sleep and feeding schedule for the baby's first month. This means they will of course recognize your face irrespective of their vision still being limited to 12 inches.

Reviewed By-

Nimrat, Pediatrics

Nimrat, Pediatrics

Dr. Nimrat S Sidhu is a practicing pediatrician for about 5 years now and holds an MD pediatrics degree. She was the topper of her batch, has always had a keen interest in her core medical field, and is specially trained for neonatal resuscitation.

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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