A Guide to Your 5-Week-Old Baby's Development

As your baby enters their second month, they're starting to reach important developmental milestones. Here's what to expect.

Your baby has completed their first month of life, and so much has changed! Although they're still really little, they're starting to feel less like a newborn, and more like a full-fledged baby. Your infant's growth is taking off by now, and you're probably finding that they've outgrown their newborn clothes and newborn diapers. You're also noticing that they're much more alert, aware of their surroundings, and engaged with you.

Five-week-old babies aren't without challenges, of course. Your little one still wakes up frequently at night, and they may not have their nights and days fully sorted out yet. They may also still be quite fussy at times or have colic symptoms.

Here, we break down what to expect when it comes to caring for a 5-week-old baby, including development, feeding, sleep, care, health, and safety.

5-week old baby milestones and development

Illustration by Joshua Seong

5-Week-Old Baby Development

Each week, your baby gets more alert, and five weeks is no exception. "[A 5-week-old baby is] just more alert and has slightly longer stretches of time to interact," says Gina Posner, MD, a pediatrician at MemorialCare Orange Coast Medical Center.

As your baby becomes more aware, they also become more social and interactive. Your baby listens more intently to sounds they hear, and their eyes will likely follow as you walk across the room. You'll probably notice that your baby’s eyes light up when you pick them up and look at them.

By now, many parents start to wonder when their baby will smile. All babies are different, but sometime in the next few weeks, usually by the 2-month mark, your baby will have their first social smile.

That said, some babies may already be smiling, according to Daniel Ganjian, MD, a pediatrician at Providence Saint John’s Health Center in Santa Monica, California. He says that by 4 to 5 weeks, babies will occasionally smile, but this will increase in frequency as you get close to the 6-week to 8-week mark.

Of course, all babies develop at different rates, so if your baby shows no signs of smiling yet, don’t worry. You will start seeing glimmers of that first smile in no time!

At This Age

  • Development: Your baby’s newborn reflexes are starting to disappear, they're starting to become more social, and their movements are becoming more deliberate.
  • Sleep: Your baby still sleeps an average of 15.5 hours a day, but they're getting closer to distinguishing night from day.
  • Food: If you're formula feeding, the amount you give your baby may increase this week; breastfed babies might be trying their first bottle this week.

5-Week-Old Baby Milestones

As your baby moves out of the newborn phase, the reflexes you may have noticed at birth—the startle reflex, the rooting reflex, the “stepping” reflex—may start to decrease. With that, you may notice your baby’s movements becoming a little more deliberate.

You can see these more conscious movements in the ways that your baby uses their hands. They may look at their hands and realize they can move them right into their mouth. What a cool skill!

If you lay your baby under a crib mobile or a play gym mobile, they might use their hands to try swiping at it. Additionally, if you place a rattle or toy in your baby’s hand, they may grasp the toy for a short time before they drop it. Before you know it, they'll start to hold onto toys for longer and longer.

5-Week-Old Baby Growth

At this point, your baby should be steadily gaining weight. Every baby has their own growth curve, but on average, babies are starting to gain about 1.5-2 pounds per month, and they grow about an inch in length each month. Your baby’s head size with grow by about 0.5 inches per month as well.

5-Week-Old Baby Feeding

By now, you’ve probably got into a feeding routine with your baby. Here's what breastfeeding and formula-feeding parents need to know, including how much a 5-week-old should eat.

Breastfeeding a 5-week-old baby

If you're breastfeeding, you should still expect to nurse quite frequently at this age. Most babies require eight to 12 feedings in 24 hours.

Dr. Posner encourages nursing parents to practice responsive feeding at this age. “Babies can still breastfeed on demand—usually they will want to breastfeed every two to four hours at this stage,” she notes. “But sometimes they'll want to feed every hour and other times will not eat for five hours.” All of this is common, she says.

Formula-feeding a 5-week-old baby

If you're using formula, your pediatrician might advise you to increase the volume you feed your baby around five weeks. When your baby was a newborn, they generally drank 1-2 ounces of formula at a time, according to the American Academy of Pediatrics (AAP). But by the end of the first month, that amount probably increased to at least 3-4 ounces per feeding, about every three or four hours.

As you move past the first month of life, your baby will generally start to go longer between feedings. All babies are different, though, and you should continue to read your baby’s cues when it comes to hunger.

Introducing a bottle to a breastfed baby

Five weeks is also when breastfeeding parents might introduce their first bottle, usually in preparation for an eventual return to work. Most experts recommend that you breastfeed exclusively, without bottles, for the first 3 weeks to 4 weeks of life, especially as your baby is getting used to breastfeeding. But starting around now, you can introduce the bottle.

When you first introduce a bottle to a breastfed baby, it’s normal if they look at it like, “Hey, what’s this?” Eventually, though, they'll get used to it. At first, it can be helpful to have someone other than the breastfeeding parent feed with the bottle, so it’s less confusing for your little one. You can also try bottle feeding in different locations than where you normally nurse. Making bottle feeding fun and playful can also help.

What About 5-Week-Old Baby Poop?

You may also start noticing that your baby’s poops have started to slow down. Many parents get worried about this, but it’s also quite common, says Dr. Ganjian. Poop schedules change around five or six weeks, becoming less frequent. “As long as the stools are not hard and are occurring every five days, it's OK to just monitor. If you have any questions, speak to your pediatrician," says Dr. Ganjian.

 5-Week-Old Baby Sleep

Five weeks is still a time marked by sleep, though not always with many hours in a row. Your 5-week-old baby sleeps an average of 15.5 hours out of 24 hours, with about seven hours of sleep happening during the daytime, and about eight or nine hours happening at night.

“Five-week-old babies are still sleeping the majority of the day off and on,” says Dr. Posner. One highlight is that they're starting to understand the difference between night and day a little better, she says, and that can come as a big relief to parents.

As time goes on, your baby will sleep fewer hours during the day and do the bulk of their sleeping at night. But your little one isn't quite there yet. Baby steps, as they say.

In the meantime, you can teach your baby that nighttime is for sleeping by establishing a bedtime routine. For example, around the time when they usually get sleepy at night, dim the lights and play soft music. Some babies find baths relaxing; others might like a baby massage. The idea is to signal to your baby that it’s time to relax into sleep.

5-Week-Old Baby Schedule

As your baby becomes more alert and has longer stretches of awake time, you'll start to integrate them more into the schedule of your home. Indeed, your little one might even want to play several times each day!

Setting up a few “stations” in your house where you can give your baby playtime—or set them down for a second while you take care of something around the house—can be helpful. If possible, consider investing in a baby gym or baby activity center. For those times when you need to keep your baby safely contained for a few minutes, having a playpen around can be a lifesaver.

Seeking Support During At Week Five

If you have any questions about your baby’s behavior or development, or if you're feeling more than just a little overwhelmed, don’t hesitate to reach out to a health care professional for support and advice.

5-Week-Old Baby Health and Safety

After your baby’s 1 month visit, they won’t see the pediatrician until 2 months. Now is a good time to make your 2-month appointment, if you haven’t already. Also, know that even if you don't have a scheduled visit with your pediatrician, you can call them with questions or concerns.

Your baby isn’t mobile yet, so you don’t have to start babyproofing your home with things like outlet covers and kitchen cabinet locks (this will come later!). That said, you can still take some measures to make your home’s environment as safe as possible for your growing baby. Here are a few tips to keep in mind.

Fire and carbon monoxide detectors

Most of us have smoke alarms in our homes, but it’s important that you also install a carbon monoxide detector. You should have at least one carbon monoxide detector on every floor of your house. Check that both your smoke alarm and carbon monoxide alarm batteries are in working order. Continue to check these once every six months or so.

Window cords

You might think your 5-week-old baby is too little to play with a window cord, but as they get better at grabbing things with their little hands, they might end up pulling on one. Most window cord injuries happen to young children, so ensure that all curtain or blind cords are completely out of reach of your baby—especially ones near your baby’s changing table, crib, or anywhere you set them down.

Smoking and vaping

Second-hand smoke is dangerous to everyone, but babies are particularly vulnerable to it. No one should smoke or vape inside the same house as your baby; even smoking in a different room comes with risks. It’s best to refrain from smoking or vaping altogether, but if you must, do it outside your home.

5-Week-Old Baby Care Basics

At five weeks, you might wonder how to calm your baby’s fussiness, as colicky symptoms tend to peak around this time. Even babies who don’t exhibit signs of colic often are extra fussy and irritable in the evening. Researchers believe this is because of the rapid changes that happen as your baby’s central nervous system starts to develop.

So what should you do about all the crying and fussiness? You usually need to wait it out; colicky crying doesn't usually last longer than 6 months.

That said, the AAP explains that colic and fussiness can sometimes be caused by a reaction to something in your breast milk, so eliminating dairy products and other irritants might help; discuss this option with your child's pediatrician. You might need to do some experimenting to discover what's causing the reaction. If you're formula feeding, consider switching formulas, with your pediatrician's approval. In either case, take care not to overfeed your baby, as that can upset their tummy as well.

Other tried-and-true ways to soothe a fussy baby include:

  • Swaddling them
  • Offering a pacifier
  • Walking them in a baby carrier
  • Holding them while you bounce on an exercise ball
  • Using a white noise machine or shushing them

If nothing you're doing seems to help, and your baby is inconsolable, you should consider calling your doctor to rule out any medical issues.

What Else to Know About Your 5-Week-Old Baby

Five weeks is a bit of a transition time for you and your baby. Your infant may be literally transitioning out of their newborn clothing, in fact, and they're becoming more like a little person. You might be thinking about returning to work, and what that will mean for you and your baby.

Be gentle with yourself as you face these changes and transitions. Some of them may make you feel sad and nostalgic, while others may be confusing and challenging. You should know that you aren’t alone. Many parents have faced similar transitions with their babies.

It’s normal to feel like you need to talk with someone during this time. Consider joining a new parent support group, or connecting with a counselor or therapist who can listen to your concerns and help you sort out your feelings.

Key Takeaways

By five weeks, you probably feel like you’ve mastered feeding your baby, changing their diaper, and taking care of their other basic needs. Your baby’s fussiness should resolve in a few weeks, and their sleep should start getting a little better soon. Hang in there, and try to remember that it’s normal to feel a little overwhelmed during this stage.

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Sources
Parents 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.
  1. 1-3 Months Old Baby Development. Children’s Health Orange County. Reviewed 2021.

  2. Newborn Reflexes. American Academy of Pediatrics. Updated 2022.

  3. Infant Sleep. Stanford Children’s Health.

  4. Amount and Schedule of Baby Formula Feedings. American Academy of Pediatrics. 2022.

  5. Planning to Be Away from Your Baby: Introducing a Bottle. Stanford Children’s Health.

  6. How Much and How Often to Breastfeed. Centers for Disease Control and Prevention. Reviewed 2022.

  7. Amount and Schedule of Baby Formula Feedings. American Academy of Pediatrics. 2022.

  8. When to Introduce the Bottle. American Pregnancy Association.

  9. Newborn Breastfeeding Basics. Centers for Disease Control and Prevention. Reviewed 2023.

  10. Infant Sleep. Stanford Children’s Health.

  11. AAP Schedule of Well-Child Care Visits. American Academy of Pediatrics. Updated 2023.

  12. Carbon Monoxide Poisoning: How to Protect Your Family. American Academy of Pediatrics. Updated 2022.

  13. Pediatric Injuries Related to Window Blinds, Shades, and Cords. American Academy of Pediatrics. 2018.

  14. The Dangers of Secondhand Smoke. American Academy of Pediatrics. Updated 2017.

  15. Colic Relief Tips for Parents. American Academy of Pediatrics. Updated 2022.

  16. Evidence-based milestone ages as a framework for developmental surveillancePaediatrics & Child Health. 2012.

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