Your 4-Week-Old Baby’s Milestones & Development

It may be hard to believe that an entire month has gone by already! Your baby is still very much a newborn and continues to spend most of the day eating and sleeping. But this week, your baby is gaining even more awareness of their surroundings, becoming stronger, and (hopefully) beginning to learn the difference between day and night.

You are probably finding your groove by now, but if you are finding this stage challenging, you are not alone. Four-week-old babies still don’t sleep through the night, they often need to eat very frequently, and many have fussy evenings, or even signs of colic. But much of this is outweighed by the fact that they are starting to become more alert and interactive.

Let’s take a look at what exciting milestones to look for this week, and what to know about 4-week-old sleep, feeding, baby care, and safety.

At This Age

  • Development: Your baby is becoming more aware of you, and may turn to you when they hear your voice.
  • Sleep: Your baby still spends most of the day sleeping, and still wakes up frequently at night.
  • Food: Babies this age have varying eating patterns, but you know your baby is getting enough by how well they are gaining weight.
4-week old baby milestones and development
Illustration by Joshua Seong, Verywell

4-Week-Old Baby Development

Gina Posner, MD, a pediatrician at MemorialCare Orange Coast Medical Center in Fountain Valley, CA, says that at 4 weeks old, your baby is really starting to become more communicative and responsive. “They start looking around more and responding to sound,” she says.

You may notice that your baby turns their head to you when you walk in the room, especially if they can hear the sound of your voice. Your baby can still only see well a few inches in front of them, but you may notice that they are particularly enthusiastic when it’s your face they see from that distance. Babies this age are most excited by other humans, especially their family members.

Unfortunately, this is also a time when your baby is extra fussy and may be exhibiting signs of colic, or inconsolable crying. Usually colic starts at around 3 weeks old, but it can start at 4 weeks, too. Colic tends to peak at 4 to 6 weeks, so it’s possible that you may be in the thick of it right now. Try to keep in mind that colic does pass eventually. It usually starts to get better at around 6 weeks and is resolved by 12 weeks. Reach out to your pediatrician with any questions or concerns you may have about your baby’s crying.

Although 4 weeks is often a time of more awareness and interaction, many babies are still spending most of their time sleeping and not doing much else. Christina Johns, MD, pediatrician and senior medical advisor at PM Pediatrics, urges parents not to worry too much if they don’t feel that their baby is very alert at this age.

“At four weeks, lots of parents wonder when their baby will start to wake up a little and show some of their personality,” Dr. Johns says. “In the first month of life, newborns mostly sleep and eat and create messy diapers, so it can sometimes feel like there isn’t as much bonding going on as a parent might like.”

Try to be patient, Dr. Johns advises. There will be lots of developmental changes happening in the next few weeks, and your baby is sure to show a little more personality soon.

All babies are different and grow at their own pace. Still, 4 weeks marks a time when your baby should begin to grow pretty rapidly. Starting at about one month, your baby should be gaining about 1 ½ to 2 pounds per month. They should grow about one inch in length per month, and their head circumference should increase by about ½ inch per month.

4-Week-Old Baby Milestones

As your baby grows, they are getting stronger and stronger. If you put your baby on their belly for tummy time, you may notice that they are better able to lift their head up. They may even be able to move their head from side to side at this age. You may also notice that your baby is able to hold their head up more steadily when you hold them, though you should still be supporting their head while holding them.

When your baby was first born, their movements were likely very jerky and uncoordinated. You should start to see more deliberate movements from your baby at 4 weeks. As an example, you may notice that your baby more deliberately lifts their hands toward their mouth. Soon, they will discover how to purposefully put their hands in their mouth (get ready for lots of finger and fist sucking!).

At this age, many parents are worried if their baby hasn’t met certain milestones. It may be too soon to tell if your baby is behind—after all, they are only a few weeks old!—but the American Academy of Pediatrics (AAP) advises that you consult your baby’s pediatrician if you see any concerning signs of developmental delays.

Call your pediatrician include if your baby is not suckling well and takes a long time to feed. Additionally, if you notice your baby doesn’t follow objects that are close by, doesn’t blink when they see a bright light, or doesn’t respond to sounds, get in touch with your doctor. Other concerns include if your baby continues to seem droopy, hasn’t gained strength since birth, or doesn’t seem to move their arms and legs very often.

Additional Behaviors

Some other milestones you may notice by the time your baby reaches 4 weeks include:

  • Begins to study your face
  • May hold their hands in tight fists
  • Gets excited when you speak or start signing
  • Is beginning to extend their legs more often, rather than keeping them flexed
  • Continues to have many newborn reflexes, including rooting, startling, and grasping

4-Week-Old Baby Food

At 4 weeks old, your baby should be well over their birth weight and beginning to gain weight steadily, Dr. Johns says. As for feeding patterns, all babies are different, and you don’t really need to count feedings anymore or log every feeding as you might have in the early days. “Feeding is very variable at this age, and the most important metric is weight gain,” Dr. Johns recommends.

Dr. Posner suggests that parents continue to feed their babies responsively, and according to their baby’s cues. “I am a big fan of feeding on demand,” Dr. Posner says. “At this stage, most infants are good at knowing when they are full and when they are hungry.”

For breastfed babies, she recommends you feed your baby on demand. Most breastfed babies still feed about eight to 12 times a day at this age. If you are formula-feeding, Dr. Posner recommends starting at 2 ounces and then increasing by an ounce at a time if your baby fusses or seems to want more.

Dr. Johns says that one of the top concerns she sees about baby feeding at 4 months old has to do with pooping patterns. When your baby was a newborn, they may have pooped very frequently, sometimes after every feeding. But it’s normal if things are starting to slow down by now.

“Parents often ask about bowel patterns, and they can be very variable at this age, ranging from three times a day to three times a week, and all are normal,” Dr. Johns assures.

Another issue many parents grapple with at 4 weeks is spitting up. You can take heart knowing that spitting up is mostly just a laundry issue. Stock up on burp cloths now if you haven’t already!

“Spitting up is a big concern from most parents,” says Dr. Posner. “I explain that as long as the baby is gaining weight well and not in a lot of pain, this is normal.”

If your baby seems to be uncomfortable after feeding and/or is fussing, spitting up excessively, or arching their back as in pain after feeding, your baby may be experiencing infant reflux. If you suspect that your baby has reflux, you should speak to their pediatrician.

They may suggest things like making sure to burp your baby after feeding, offering smaller, more frequent meals instead of larger ones, and holding your baby upright after feeding. In some cases, a medication that neutralizes stomach acid may be recommended by your doctor.

4-Week-Old Baby Sleep

Sleeping is still one of your baby’s favorite pastimes at this age. You can expect a 4-week-old baby to sleep a little over 15 hours a day. This will be pretty evenly divided between night and day, though your baby may be moving toward doing a little more of that sleeping at night. Most babies this age sleep about eight to nine hours total at night, and about seven hours total during the day.

Your baby’s nighttime sleep is likely still broken up with frequent wake-ups, usually because of hunger. This is common, but it’s also normal to feel frustrated by this!

Dr. Posner says that the biggest question her patients have about sleep at this age is when their babies will sleep through the night. “They sleep a lot, but not in large stretches, so expecting them to sleep through the night at this age is a dream, not reality,” she says.

Some babies sleep longer stretches starting at 3 months, or when they have reached 12 or 13 pounds. But this varies tremendously, and some babies don’t start sleeping more soundly for several more months. Hang in there—your baby will get there soon enough.

Four weeks is still a time when you need to be extra cognizant of the danger of SIDS (Sudden Infant Death Syndrome). The AAP recommends that you keep your baby in your room, but not in your bed. You should put your baby to sleep on their back on a firm mattress without any blankets, pillows, toys, or crib bumpers. The AAP does not recommend at-home heart or breathing monitors.

4-Week-Old Baby Schedule

At 4 weeks, while your baby doesn’t yet have a clearly defined schedule, you and your baby are probably starting to get into a bit of a routine. With your baby doing a little less sleeping during the day, and a little more sleeping at night, you might even be able to predict when your baby tends to need naps, and when they are more awake and alert.

Now that your baby is becoming stronger and more aware of their surroundings, tummy time will become even more enjoyable. The AAP recommends that you do tummy time a few minutes at a time, several times a day. At this age, you can make it part of your daily routine.

You don’t need much equipment for tummy time, but as your baby gets older, they may enjoy a play gym that has mobiles or other bright patterns. Your baby may also enjoy a baby swing at this age during those more alert times of the day. Your baby may especially enjoy baby swings with bright lights and music.

4-Week-Old Baby Health and Safety

At 4 weeks old, your baby will have their first well-baby visit since they were a few days old. This is an exciting moment for you and your little one.

You are likely to have lots of questions about your baby’s growth and development. Your pediatrician will ask you questions about what your baby is doing at this age, and you can also come prepared to the visit with all your lingering questions. Don’t be afraid to voice any concerns you have, big or small.

Vaccinations

At this visit, your baby will probably get their second hepatitis B vaccination; however, some pediatricians give this vaccine at the 2-month visit. Your baby's next visit will be at 2 months. At the 4 week visit you can take some time to ask your pediatrician what to expect at this next visit, and how to prepare.

Car Seat Safety

Your pediatrician will verify that your baby is using a car seat. Babies this age should be using an infant car seat, and should continue to be rear-facing at this time. Your doctor will likely emphasize that your baby should stay in the car seat while traveling in the car. Car seats shouldn’t be used for napping out of the car, and shouldn’t be used while feeding.

Safe Sleep

Sleep will be discussed at this visit as well. Your baby’s pediatrician will emphasize the importance of safe sleep and will remind you to always put your baby to sleep on their back, in a crib or bassinet.

They will remind you not to share sleep with your baby and underline the dangers of falling asleep with your baby on a couch, recliner, or armchair, or while under the influence of drugs or other medication.

4-Week-Old Baby Care Basics

Your baby care still revolves heavily around—you guessed it—diaper changes! Expect to change six diapers a day, sometimes more.

At this age, you might notice that your baby is prone to some skin irritation in their diaper area. Diaper rash is common, especially for babies who are peeing and pooping as often as a 4-week-old is.

If you are starting to see more diaper rashes right now, don’t despair. This is common, and there are things you can do to keep your baby’s bum clear and less irritated.

The AAP recommends changing your baby’s diaper frequently so they don’t sit in wetness too long. Consider using a highly absorbent diaper, especially at night. Clean your baby’s diaper area well after changing them, and consider applying a barrier cream, such as one with zinc oxide or petrolatum.

What Else to Know About Your 4-Week-Old Baby

As you settle into your role as the parent of a young baby, you are going to get lots of advice—some of it helpful, some of it less so. It’s important to remember that you are the parent here, and are ultimately the one who makes decisions about how to care for your baby.

First and foremost, follow safety instructions from your pediatrician, especially when it comes to safe sleeping, feeding, car seat safety, and basic healthcare. But questions like how to feed your baby, how often you need to pick your baby up when they fuss or cry, and whether it’s the right time to think about returning to work, are really up to you!

As long as your baby is fed and cared for, it doesn’t matter exactly how that looks. It’s all a matter of what works for your and your family.

A Word From Verywell

Although many parents start to feel like they are getting the hang of things at 4 weeks, if you still feel like you kind of don’t know exactly what you are doing, that’s also perfectly common! Besides the fact that you and your baby are still getting to know each other, and you are still coming into your own as the parent to this particular little person, 4 weeks is also the peak of colic, which can be exhausting and disorienting.

If you are dealing with a fussy or colicky baby, try to accept any help that’s offered. You will need extra help around the house, and you definitely deserve a few extra naps. Getting some fresh air can help both you and your baby feel better during fussy times. Always reach out to your pediatrician if you have any questions about your baby’s behavior, care needs, or overall health.

Frequently Asked Questions

  • How long do 4-week-old babies sleep?

    4-week-olds are still sleeping most of the time. You can expect your baby to sleep a total of about 15 hours a day.

  • How far can newborns see at 4 weeks?

    At 4 weeks, your baby can usually only see about 8 to 12 inches ahead.

  • What can a 4-week-old baby do?

    By 4 weeks, your baby can lift their head up a little, they are becoming a little more deliberate in their movements, and may be beginning to recognize their parents’ faces and voices.

  • Can babies laugh at 4 weeks?

    Your baby isn’t laughing yet, but this should happen within the next few weeks!

  • How much should a 4-week- old weigh?

    Your baby has surpassed their birth weight by now and has begun to steadily gain weight. All babies are different, so there is no one right weight for a 4-week-old. At this age, you can expect your baby to start gaining 1 ½ to 2 pounds per month.

  • How often should I feed my 4-week-old baby?

    Continue to feed your baby on demand at this age. Breastfed babies usually feed 8 to 12 times in 24 hours, and formula-fed babies usually take in about 24 ounces of formula in a day.

  • Do babies get easier at 4 weeks?

    Parents are often getting more comfortable caring for and understanding their baby’s needs. However, 4 weeks is also a time of increased fussiness and sometimes colic, so in some ways, 4 weeks is a tougher time for parents. This fussy period should subside in the next few weeks.

12 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. American Academy of Pediatrics. Developmental milestones: 1 month.

  3. U.S. National Library of Medicine. Colic and crying - self-care.

  4. Nemours KidsHealth. Your newborn's growth.

  5. Stanford Children’s Health. The growing child: 1 to 3 months.

  6. Nemours KidsHealth. Your child's checkup: 1 month.

  7. Porto A. Gastroesophageal reflux & gastroesophageal reflux disease: Parent FAQs. American Academy of Pediatrics.

  8. Moon R. How to keep your sleeping baby safe: AAP policy explained. American Academy of Pediatrics.

  9. American Academy of Pediatrics. Back to sleep, tummy to play.

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  12. American Academy of Pediatrics. Common diaper rashes and treatments.

By Wendy Wisner
Wendy Wisner is a lactation consultant and writer covering maternal/child health, parenting, general health and wellness, and mental health. She has worked with breastfeeding parents for over a decade, and is a mom to two boys.

Originally written by
Chaunie Brusie, RN
Chaunie Brusie, RN
Chaunie Brusie is a registered nurse with experience in long-term, critical care, and obstetrical and pediatric nursing.
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