Your 3-Week-Old Baby

At three weeks old, your baby may still feel brand new, but subtle changes are happening every day. You might notice the tiniest shifts in their feeding, sleeping and waking rhythms, and you’re hopefully gaining more confidence in your own instincts and abilities as a new parent. 

By this point, your baby is showing more definite signs of growth, including weight gain, strength and coordination (especially during tummy time), but you may also notice that they’re gassier, too. We've got tips from Dr. Chris Klunk, board-certified neonatologist at Pediatrix Medical Group, on how to support baby's growth while also keeping them comfortable.

As for your own development as a parent, now’s a good time to check in with your own well-being, especially your nutrition and sleep—both of which are vital not only for postpartum recovery, but for overall functioning even if you didn’t give birth. Dr. Faith Ohuoba, a Houston-based ob-gyn, has advice on how to make sure you’re doing what’s best for your body and mind so that you’re not completely burning out in these early newborn weeks.

🚼 Baby’s Development 

⚖️ Back to Birth Weight

In week one, we talked about how babies typically lose up to 10% of their bodyweight in those first few days. ​​By the third week, your newborn should be officially back to their birth weight and continuing to gain weight steadily. This is a good sign that your baby is feeding well—whether via breast, bottle or both—and that their development is on track. From this point until about four months old, you can expect your baby to gain about an ounce per day, no matter what growth percentile they’re in.

💨 Gassiness on the Rise

It is important to note that “colic” is a medical term for excessive or persistent crying in a newborn and does not necessarily mean pain, gas, constipation or anything more specific. Just like we can cry a bunch for all sorts of reasons, babies can too. Most clinicians define colic as crying for 3 or more hours a day, 3 or more days per week, which is a lot, but also very expected.

Babies get gas in the process of digestion just like their parents, though they may handle it with a little less grace. Gas discomfort is thought to peak around 6-8 weeks of age and some parents have success reducing gas by changing bottle and nipple types, using premixed formula rather than mixing their own (which may introduce air during mixing) and burping during and after feeds. Anti-gas drops come in all sorts of shapes and sizes but generally contain the same ingredient, Mylicon. While there is no real evidence that Mylicon causes any harm, except perhaps to your wallet, there is also no significant evidence that it does any good.

Gassiness is a pretty common thing in newborns, especially during the first few months. Don’t be surprised if, right around now, you notice your baby starting to get a little fussier, crankier and, well, fart-ier. Their digestive system is still maturing, and things aren’t working optimally just yet. 

Especially if you have a heavier or forceful letdown (when your breastmilk is first released as baby starts nursing) or if your baby drinks from a non-vented bottle (a bottle that doesn’t say “anti-colic” or “anti-gas”), they might be getting a lot of air in their system as they’re eating, which can lead to bloating, discomfort and (understandably) fussiness. Here’s what you can do to help:

• Make sure you’re thoroughly burping your baby during and after every feed (more on how to burp your baby below).

• Slow baby’s eating, either with a slower-flow nipple or by having them take more frequent breaks.

• If bottle feeding, switch to a vented, anti-colic bottle.

• Have baby sit in a supported, upright position while eating and for at least 10 minutes after eating.

• Gently massage baby’s tummy in a clockwise direction.

• Bicycle their legs.

• Do tummy time (in short bursts)—more on why that works for gassiness in a moment.

• Give baby a soothing warm bath to help them relax their muscles.

• Try simethicone gas drops (with your pediatrician’s approval).

When to talk to the doctor: If your baby is crying for more than three hours a day, more than three days a week, for at least three weeks, let your pediatrician know. That level of excessive crying is known as colic, which you might've heard of as a potential condition. But while it may be linked to gassiness, Dr. Klunk says to keep in mind that "colic" is just a medical term to define the amount of crying.

"It does not necessarily mean pain, gas, constipation or anything more specific. Just like we can cry a bunch for all sorts of reasons, babies can too." Your baby's pediatrician can help you better narrow down the cause of the fussiness and whether anti-gas treatments are appropriate.

💡 Try This with Baby: Tummy Time

Tummy time can be a great opportunity for bonding with your baby, but it’s also really important for their muscle and motor skill development. "The American Academy of Pediatrics recommends introducing tummy time right from day one after getting home from the hospital," Dr. Klunk says. But if you haven't tried it by week three, it's never too late to start!

Keep things short and sweet, at first—baby will have the next several weeks and months to build up to longer stretches. "Start [with] two to three times a day for three to five minutes, and gradually work toward 30 minutes a day by seven weeks," Dr. Klunk advises.

Just those few minutes a day helps develop your baby’s neck, chest, arm, upper back and core muscles, Dr. Klunk says, paving the way for future gross motor skills like rolling, sitting, crawling, walking and more. 

Regular tummy time sessions can also give the back of baby's head a rest, Dr. Klunk says, which will help prevent flat head syndrome—when babies spend too much time on their backs. And given that babies need to be placed on their backs for safe sleep, it’s understandable that they’d spend a lot of time in that position. So it’s important to give your little one the opportunity to wiggle around on their belly instead, letting the back of their head take a break from the floor.

And finally, like we mentioned above, tummy time can actually help relieve gassiness. The wiggling and activation of core muscles can help baby get things moving along in their digestive tract.

Just keep in mind that some babies may not enjoy tummy time at first (might rage against the playmat, honestly), especially if they’re already uncomfortable with trapped gas. So be sure to limit tummy time to just a few minutes a couple times a day at first, then increase the timing as baby gets better at tolerating it. 

💗 You, 3 Weeks After Baby 

🧑‍⚕️ Your Physical Health 

As you’re physically and emotionally adjusting to being a parent, whether you’re recovering from childbirth or not, one of the most important yet often overlooked elements is nutrition. Eating well isn’t just about fueling your day—it’s about supporting your body as it heals and adjusts to new physical demands, like changes in your sleep schedule and the general physical toll of caring for a baby.

Especially if you’re nursing or pumping, “nutrition is important [as a] building block for breast milk,” Dr. Faith says. She emphasizes that having a well-balanced diet that includes protein, iron and whole grains, as well as good hydration, will help with milk production.

Nursing and pumping parents should be eating extra calories in general—breastfeeding burns calories, and you’ll need to make sure you’re making up for that deficit in order to keep your milk production steady. 

Even if you’re not nursing, nourishing your body with high-quality foods like lean proteins, leafy greens, whole grains, fruits and healthy fats will help replenish all the nutrients you may be losing during these early weeks of intense caregiving, especially if you’re recovering from giving birth, too. “Protein is also important when it comes to wound healing,” Dr. Faith says, “especially if you had a C-section.”

When you’re so focused on making sure your baby is healthy and thriving, maintaining a regular meal schedule for yourself can be tough. But if you’re skipping meals (whether intentionally or not) or surviving on processed snacks, you’re going to see it take a toll on your energy levels and overall mood.

This is a great time to call in reinforcements. Ask your loved ones to start a meal train or bring you some easy-prep meal kits to ensure you’re taking care of your own nutrition.

For your part, stock up on non-processed, easy-to-grab, nutrient-dense snacks like yogurt, trail mix, hard-boiled eggs and fruit, and keep a water bottle within reach at all times. You don’t need to aim for perfect meals; think of eating as an essential part of caring for yourself—because it is.

🧠 Your Mental Health 

Sleep deprivation is infamously one of the toughest parts of new parenthood, and it can have a profound effect on your emotional well-being. While it’s totally normal to feel tired and occasionally overwhelmed during these early weeks, regularly missing out on a full night of restorative sleep can make things infinitely worse. 

Mood swings, irritability, anxiety, sadness and an increased risk of developing postpartum depression are just some of the side effects of not getting enough sleep, not to mention brain fog and slowed reaction times, which can put both your own and your baby’s safety at risk. That’s why finding ways to prioritize quality sleep is really, really important, especially right now.

“Sleep hygiene is critical for living well and holistically,” Dr. Faith says. “This is especially important for new parents because of the new demands the newborn will place. The short duration or bursts of sleep can be stressful for a new parent.”

But even if you strictly follow the age-old advice of “sleep when the baby sleeps,” that’s not going to get you more than two hours at a time during the newborn stage—hardly enough for restorative rest. So what are you supposed to do? 

“Creating a sleep plan or rotation is one of the ways parents can make sure they are getting enough good sleep,” Dr. Faith suggests. “The plan should allow for each caregiver to obtain adequate rest.”

Whether you’re parenting with a partner or other family or friend support, it’s a really smart idea to take turns with nighttime responsibilities. A shared schedule—like alternating night shifts or dividing early mornings and late nights—can make a significant difference in how rested you feel.

Here's a sample schedule for two caregivers trading between overnight feeding duties and sleep. You can always adjust the hours for what works for you—a schedule like this one ensures that each partner gets four hour stretches of uninterrupted sleep. But keep in mind that at least one person will need to bottle feed, so if you're breastfeeding and haven't introduced a bottle yet by week three, this is a great time to discuss it (we'll talk about this a little more in the Feeding section below).

If you’re parenting solo or find yourself doing most of the caregiving, try recruiting any friends and family you trust to help watch your baby for just a couple of hours—especially the ones who want to help but aren’t sure how. Let them come over and hold the baby while you take a short nap. 

Even without extra help, small adjustments can make a difference. Sleep when your baby sleeps so that you can at least ensure those small bursts (as short-lived and sometimes frustrating as they are), and even when baby isn’t sleeping, dimming the lights and avoiding screens in the evening can help encourage both you and baby to wind down and at least relax a little easier.

And remember, if the lack of sleep and emotional load feel too heavy, it’s okay to ask for help. Your ob-gyn should be able to provide resources and suggestions to ensure you’re getting the rest and support you need. 

🧑‍🍼 Feeding Baby 

🍼 Week 3 Feeding Guidelines

• Breastfed babies: Feed as often as they show hunger cues—this might mean every 1–3 hours, or about 8–12 times in a day (including nighttime feedings).

• Formula-fed babies: Offer 2–3 ounces per feed, about 8–12 times per day.

😋 Growth Spurt = Hungrier Baby

Some babies may have a small growth spurt right around this time, which can increase how hungry they are. It usually lasts two to three days—just watch for hunger cues like rooting or sucking on their hands, and if baby still has these cues even after eating their regular amount, it’s okay to give them more than usual, just a little bit at a time.

Cluster feeding, or frequent feeds in a short span (which we’ll go over next week) is normal during a growth spurt, especially in the evenings.

🤝 How to Coordinate Feedings with Partners & Helpers 

Feeding a newborn—whether breastfed, formula-fed or both—can feel relentless in these early weeks. But you don’t have to shoulder it all alone. If you have a partner, co-parent or support person, coordinating feedings is not only helpful for your baby—it’s also a critical part of supporting your own mental health and getting the rest you need.

Like the chart above shows, taking turns with feedings can help ensure both you and your partner are getting periods of restorative rest. If you’re breastfeeding, pumping and storing milk gives your partner the ability to take over some of those feedings. If you’re formula feeding, it can be even easier to share the load evenly.

If you've been breastfeeding for the past three weeks and are considering introducing a bottle in order to share the feeding duties, it's a good idea to reach out to a lactation consultant for guidance on how to do that. And we'll be digging a little deeper into combination feeding (breast + bottle) next week, too.

Tools like feeding logs or baby-tracking apps can be a game changer here too. Not only do they keep everyone on the same page about feeding times and amounts, they also help identify patterns and anticipate baby’s needs—saving you mental energy during an already exhausting time.

Coordinated feeding responsibilities aren’t just about efficiency; they’re about building a support system that protects your well-being and creates space for everyone in the home to rest and recover.

😴 Sleep 

🛏️ Total Sleep: 14–18 Hours

At three weeks old, your baby still sleeps in 1–2 hour stretches around the clock. For parents running on very little sleep, this fragmented pattern can feel exhausting. It helps to remember that your baby’s erratic sleep isn’t something you’re doing wrong—it’s developmentally normal. Baby’s not ready for a strict sleep routine just yet, so structuring your sleep support system around your own sleep needs can help everything run smoother.

🫩 How to Avoid Getting Nap-Trapped

It’s a reality many new parents face: your baby naps peacefully on your chest, usually after a feeding, but the moment you try to lay them down, they wake up and cry (thanks, startle reflex). It’s frustrating and exhausting, especially when you’re running on very little sleep.

The truth is, your body is your baby’s favorite place to be right now. They’ve just spent nine months being held 24/7, so your warmth, smell and heartbeat are the absolute most comforting things. While that’s great for bonding, it can make getting rest (for both of you) a challenge.

The key to laying baby down in their sleep space without letting them know it’s happening is to (safely) maintain that feeling of closeness and comfort while also ensuring they sleep independently. To make the transition easier, try these steps: 

• Warm the bassinet or crib with a low-level heating pad or hot water bottle. Just be sure to remove it before placing baby down.

• Swaddle securely—you want baby to feel like they’re still being held, but not too tight. And a loose swaddle is actually a hazard, according to safe sleep guidelines.

• Use white noise to mimic the sounds of the womb. 

• Lower baby slowly into their crib or bassinet, keeping them close to your chest all the way down. This may be a bit challenging depending on your height, but it’s that sudden pull away from your chest and the resulting cold that can wake baby up. The longer you can hold them to your chest while slowly lowering them down, the better. You may end up sort of face-planting halfway into the crib, but as long as you don't fall all the way in, it’s worth it.

• Keep a hand on baby’s chest for a few moments after the transfer to hold in some of that warmth from your body. You can pull your hand away millimeter by millimeter so that the loss of body heat doesn’t startle baby awake.

❓ Weekly How-To: Help Baby Burp

Earlier we talked about how babies tend to get gassier starting around week three and continuing for the next few months. One of the easiest ways to help reduce your baby’s gas and spit-up is to make sure they’re releasing any air they’ve swallowed while eating—that’s where burping comes in.

Burping a baby may seem like a no-brainer, but turns out, there’s actually a bit of technique to it. First and foremost, you want to make sure you’re burping them every time they eat. As soon as they’ve finished their bottle or pulled away from the breast, start burping them.

And if you have a particularly gassy baby, especially if they tend to eat quickly and swallow a lot of air, it’s a good idea to make them pause and burp every few minutes before continuing their meal.

So how do you do it? "Any position that allows the baby's head and chest to be supported while getting a nice pat on the back is just fine," Dr. Klunk says. Here are some safe and effective burping techniques that he suggests for a three-week-old:

• Over-the-shoulder: Hold baby upright with their chest against your chest and their head over your shoulder. Gently yet firmly pat or rub their back, starting from the lower back and working your way up to their upper back, then repeating.

• Sitting upright: While supporting their chest and head, sit baby upright on your lap, facing them outward, while gently patting their back. Keep in mind that a three-week-old can’t sit up on their own, so keep their head and upper body as upright as possible to prevent choking in case they spit up

• Face-down: Position baby tummy-down across your knees or your arm, gently supporting their chin with your hand to help keep their airways open (don’t let baby’s head fall against their chest, and be sure not to hold them around the throat). Then gently pat or rub their back.

One thing to keep in mind: it's not a guarantee that your baby will produce an audible burp. "Just don’t drive yourself crazy, as not every baby needs to burp," Dr. Klunk says. "And no baby is going to burp every single time." Pat them gently on the back for a few minutes—if nothing happens, don't stress.

🤢 When to Worry about Spit-Up

Spit-up is incredibly common in newborns, and it’s usually nothing to be alarmed about. Your baby’s digestive system is still developing, so it’s normal for some milk to come back up—especially after feeding, burping or tummy time. In most cases, it’s painless and doesn’t bother your baby, even if it leaves you running through a neverending supply of burp cloths. "A little bit of spit-up that looks like formula or milk bubbling out of the nose or mouth in an otherwise happy and content kiddo means they are what we call a 'happy spitter,'" Dr. Klunk says.

That being said, Dr. Klunk also says there are a few signs to watch for that could indicate something more serious. Call your pediatrician if:

• Your baby is projectile vomiting.

• The spit-up is green or yellow in color, or has blood or coffee-ground-like flecks. (Normal spit-up is white or cream-colored; a very, very pale yellow at most.)

• Your baby seems to be in pain or distress when spitting up—arching their back, crying inconsolably or tensing their muscles.

• You notice signs of poor weight gain (gaining less than one ounce per day) or your baby still seems hungry after eating.

• Your baby refuses feedings, turning away from the breast or bottle even after it’s been more than three to four hours since they last ate.

• Your baby is consistently coughing or choking during or after feeds, like it’s bothering their airways and affecting their ability to breathe.

Even if your baby isn’t experiencing the above symptoms, it’s always okay to check in with your pediatrician for peace of mind. In many cases, spit-up can be reduced with small adjustments, like changing your burping technique, holding baby upright after feeding or offering smaller, more frequent feedings.

Even changing baby’s formula or your own diet if you’re breastfeeding can have an effect on your baby’s spit-up. It’s worth a chat with your pediatrician if anything is concerning you.

👀 Looking Ahead 

Here’s what to look forward to in baby’s fourth week:

• Baby's first check-up: Your pediatrician will want to see your baby for a one-month well baby visit. This check-up covers growth, reflexes, feeding and early vaccinations—and you may also be screened for postpartum mood disorders. Bring questions!

• Taking baby outside: Fresh air is super beneficial for both you and baby. If you haven’t had much chance to get out of the house yet, by week four a walk around the block or a few minutes in the yard is safe and healthy. 

• Cluster feeding: Whether they’re breastfeeding or bottle feeding, some babies may cluster feed (eating smaller amounts more frequently—like the baby version of snacking) between months one and two. It can be tiring and more than a little annoying, but it’s thankfully usually pretty short-lived.

🛍️ Panic Order 

Here’s a handy collection of products you might need (or be reordering) around now:

Small Story 
Burp Cloth (4 Pack)

If spit-up increases, so does your need for burp cloths. You can never have too many.

Buy

Add to Babylist

Babylist$19.99

Lovevery 
The Play Gym

A fun and comfy mat makes tummy time more engaging.

Buy

Add to Babylist

Babylist$150.00

Amazon$150.00

Target$150.99

Little Remedies 
Gas Relief Drops - Simethicone

Eases the discomfort and pain of trapped gas. Ask your pediatrician before using.

Buy

Add to Babylist

Babylist$8.99

Amazon$7.66

Walmart$7.66

Target$7.89

Dr. Brown's 
Anti-colic Options+ Narrow Baby Bottle Starter Gift Set

Vented bottles regulate the airflow as baby drinks, helping prevent gassiness and reduce colic.

Buy

Add to Babylist

Babylist$29.99

Amazon$99.98

Babylist 
Pacifier Box (6 Pacifiers + 1 Clip)

Got a fussy baby? Try out a variety of pacifiers to see what helps soothe them. (Babies can be pretty picky about pacifiers.)

Buy

Add to Babylist

Baby Brezza 
One Step Baby Bottle Sterilizer Dryer Advanced

Vented bottles have a lot of separate parts. A bottle washer + sterilizer keeps ALL the feeding gear clean with way less effort.

Buy

Add to Babylist

Babylist$149.99

Amazon$119.99

Target$119.99

Nordstrom$149.99

Milky Mama 
Salted Caramel Lactation Cookies

Buy

Add to Babylist

milky-mama.com$17.00

MZOO 
Sleep Eye Mask

Buy

Add to Babylist

amazon.com$19.99