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10 Reasons Why Baby is Suddenly Fussy (PLUS Fast Soothing Tips!)

Babies can be fickle creatures.

They’re perfectly happy one moment and wailing the next.

Whether it’s your first baby or your fifth, at some point you will find yourself asking, “why is my baby so fussy all of a sudden? What’s wrong?”

You don’t have to be Sherlock Holmes to find the answer, but it also may not be obvious right away.

Sleep deprivation may have reduced your powers of deduction, which is why I’ve put together a list of 10 common reasons for a fussy baby.

What Does a Fussy Baby Mean?

Fussy Baby Crying Meaning

First, let’s look at some important realities.

In most situations, a fussy baby means one thing: your baby is normal. That’s right.

Take a deep breath and make yourself some calming chamomile tea – if you’re reading this article then you probably need it. I know, I’ve been there.

It’s exhausting when your baby won’t stop crying, you’re so tired, and everything seems just – so – hard.

Babies fuss for a variety of reasons depending on their age and development and for the most part, this fussiness is perfectly normal.

It’s all going to be okay.

“But my friend’s baby didn’t cry like this!”

Each baby has their own unique personality.

That’s right, from day one each baby has its own unique personality, likes, dislikes, and peculiarities.

Some babies are easy going, and some need more of your attention.

You may be tempted to compare your child to your friends’ children, or even to your own previous child, but that’s not fair to you or your baby and will only cause you more stress.

Comparison is the thief of joy, and when it comes to your baby, there’s so much joy to be had!

So whatever ideas you have about how your baby should behave, throw them out the window.

This child in your arms is unlike any other, and that’s a good thing. Enjoy him for who he is, without expectation.

With that said, there are some common patterns and reasons why your (otherwise healthy) baby might be fussy and some simple solutions to help you both get through it.

Let’s have a look at 10 common culprits.

10 Reasons Why Your Baby is Fussy All of a Sudden & How to Calm Them

1. Your Baby is Sleepy

“But he just woke up!” Babies’ bodies don’t work on the same 24 hour clock as ours, and they don’t even begin to develop melatonin until around six weeks.

According to PH.D Polly Moore, the Director of Sleep Research at California Clinical Trials in San Diego and author of The Natural Baby Sleep Solution, young babies only have an alertness cycle of 90 minutes.

That means from the moment your baby wakes up, the clock starts.

At the end of 90 minutes, they should be ready to sleep again.

Try putting a timer on it: your baby wakes up so you change his diaper. You feed him. You burp him. He sits in his bouncer for a bit and then starts to fuss. How much time has gone by? If it’s anywhere near 90 minutes, then it’s probably time to start settling down for a nap.

Babies often develop a distinct “sleepy cry” but until you begin to recognize the sounds that accompany fatigue, some other signs to look for include yawning, pulling on the ears, rubbing the eyes, or staring into space.

Don’t be surprised if your baby doesn’t do all of these. My first and third babies were screamers when they were sleepy, while my second would quietly stare into space.

When you begin to see signs that your baby is sleepy, begin your naptime routine and help them transition to sleep before they become overtired.

As babies get older their alertness cycles extend, but they still need a considerable amount of sleep throughout the day.

Most babies need 13-15 hours of sleep per day, and newborns need even more. That’s a lot of sleep!

In addition, all of us wake just a little bit between REM and non-REM sleep cycles, but young babies often have difficulty transitioning back to sleep between cycles.

So, you put your baby down for a nap and 30 minutes later he’s fussing again. This is incredibly frustrating but common. What do you do?

Well, it’s tempting to get him up but most likely he still needs to sleep.

Try soothing your baby using your preferred method and you may find that he wasn’t finished napping.

Also of note is what is commonly referred to as “the bewitching hour,” or “nighttime fussiness.”

At around 6 weeks, when their bodies begin producing melatonin, many babies go through a period of evening fussiness for 2-3 hours a night, lasting several weeks or more.

They act sleepy, but just can’t seem to settle down no matter what you try.

If they are breastfeeding, many breastfeeding moms mistakenly think that the baby is not being satisfied at the breast, when in reality they are in a state of jet lag and just can’t seem to settle down.

Be patient and enlist help from friends and family during this time.

Try wearing your baby in a wrap or carrier during the fussy hours and in a few weeks, he’ll settle down.

2. Your Baby Is Hungry

A Hungry and Fussy Baby

“But he just ate!”

Yes, it’s true. Babies eat A LOT.

If you are breastfeeding, your newborn will need to nurse often to stimulate your milk supply. They may even want to nurse every 1-2 hours in the first few weeks!

But regardless of how you feed your baby, the fact is that babies are born with a very small stomach and digest their food quickly.

In the first few days, weeks, and months, breastfed babies “cluster feed” at various stages of growth and development.

This is when they want to be at the breast for hours at a time, and it’s a good thing.

It means your baby is growing and is sending a message to your body: “make more milk!”

There’s no need to worry about your milk supply. Just put your baby to the breast until he is satisfied, even if it takes all day!

Don’t worry, most babies won’t actually take all day (though it may feel like it!).

Your body will listen to your baby’s cues and the next day you’ll have more milk.

A great resource for the breastfeeding mother is The Womanly Art of Breastfeeding.

My doctor recommended it to me before I had my first and it remains one of the most valuable resources I have had as a mother.

You may have heard friends talk about “scheduling” their baby.

Several popular books recommend following a strict schedule and have developed a devout following of parents, singing the praises of a scheduled life.

While there is no doubt that a predictable routine is good for your baby (and for your sanity), there is no “one size fits all” solution for every baby and for some babies and mothers, a strict feeding schedule can inhibit milk production and growth.

When my first was born, we struggled to develop a successful breastfeeding relationship.

After working with lactation consultants we discovered that at one week old, he was only consuming half an ounce during 45 minutes of nursing.

My baby desperately needed to nurse frequently and tell my body to produce milk. Clearly, a schedule was not going to work for him.

I needed to feed him every time he showed interest in order for us to have a happy, healthy breastfeeding relationship.

Even after my milk was established, he continued to nurse more frequently than the “textbook baby” for the first six months.

Your baby is your baby. You should never feel guilty for feeding him.

“But he’s not a newborn anymore!”

Babies go through frequent growth spurts and will need to nurse more often in order to increase your milk supply, or if bottle fed, you will need to increase the amount of formula in each bottle. But not all babies grow at the same time.

Repeat this mantra: my baby is unique.

So just because a book says your baby will have a four-month growth spurt doesn’t mean they won’t have one at three or five months!

The bottom line: babies are constantly growing and may need to eat more from time to time. Watch your baby’s cues and feed them if they seem hungry.

3. Your Baby is Thirsty

Mother Breastfeeding Newborn Baby

Until your baby begins solids (around six months, with the approval of your pediatrician), the only source of fluid and nutrition should be breastmilk or formula.

Most of the time, this isn’t a problem but especially during the Summer months you may find that your baby needs more fluids in the heat.

Breastmilk is 87% water and the first milk that comes out (called “foremilk”) has a higher percentage of water than the fatty “hindmilk” that comes out later. It’s perfect for a refreshing drink on a hot day.

Offer the breast (or a bottle) and he will probably drink just enough to quench his thirst.

4. Tummy Troubles

Baby With Painful Looking Face

After nine months of receiving everything he needs through the umbilical cord, it’s time for his digestive system to get working.

But the muscles and organs involved in the digestion process are still immature and need time to learn how to do their jobs correctly.

While his growing body figures out the kinks, your baby may experience some discomfort from time to time.

Spitting Up, Reflux, and Vomiting

When babies eat, whether from the breast or a bottle, they often swallow a good bit of air along with the milk.

This air gathers into bubbles which then *pop* their way out through a good burp. But sometimes they bring a bit of sour milk up with them.

This is perfectly normal but you can reduce the amount of spit up by being sure to burp frequently.

Burp your baby before he eats, after each ounce of formula or each breast, and after eating. Try to keep your baby upright or inclined for 20 minutes after eating.

If necessary, use a crib wedge to elevate the baby’s head and keep your baby at an incline.

Babies can also swallow air while crying, so try to limit the amount of time that he cries. This may sound like an impossible task for some babies, so take it with a grain of salt.

If your baby spits up frequently and is having trouble gaining weight, he may have reflux.

Your doctor will diagnose reflux and may prescribe medicine, or try to wait it out.

While it is frustrating to know that your baby is uncomfortable, if he is producing wet diapers and gaining weight, you can rest assured that he’ll be fine.

Occasionally, a baby may even vomit.

The difference between a regular spit up and vomit will be obvious. Spit up usually accompanies a burp, but vomit will be strong and forceful, with a lot of milk.

Don’t worry – it’s normal for babies to vomit from time to time, even without being sick. Just be sure to keep baby hydrated and if it continues, call your doctor.


She’s such a gassy baby!” I’ve found myself saying this many times about my young daughter, but the truth is, it’s true for all babies. Babies eat all day so their digestive systems are constantly working – meaning the toots just keep coming.

While some babies hardly notice when they pass gas, for others, it’s hard work. So if it seems like your baby is struggling, there are a few ways you can help.

First, try a tummy massage. Use an oil or lotion, like this California Baby Massage Oil, and massage his tummy in clockwise circular motions.

Next, channel your inner Freddie Mercury and do the bicycle. Lay your baby on his back and gently push and pull his legs in a bicycle motion.

Next, gently push both of his legs into a squat position. By the time you’ve done these three things, you’ll probably work out more than a few toots from her!

Many moms attribute a gassy baby to a food allergy or sensitivity. Dairy and wheat are popular victims and often get cut from a breastfeeding mom’s diet after a few sleepless, gassy nights. But a true food allergy will usually present itself with obvious signs.

Look for a rash, hives, eczema, congestion, persistent vomiting, wheezing, diarrhea, constipation, or stools with green mucous or blood. If you see any of these symptoms, call your pediatrician.

Your baby is more likely to have a food allergy if a close family member does, too. If there are other allergies in the family, keep track of what you are eating (if breastfeeding) and any symptoms your baby may have. Work with your pediatrician to find the culprit.

There’s no need to eliminate food from your diet on the basis of gas alone. Gas is normal. Annoying, yes, but totally normal.

If your pediatrician approves, you can try over the counter gas drops for your baby. Some parents swear by these, but scientific results are inconclusive.

So if you, like me, love a good grilled cheese sandwich, go ahead and enjoy the bread and dairy. Your baby will be gassy no matter what you eat.


Colic is defined as inconsolable crying for three hours a day, three days a week, for more than three weeks. It really is a mystery to parents and doctors alike.

Some parents associate it with tummy pain but in reality nobody really knows what causes some babies to cry incessantly for no apparent reason.

If your baby is going through colic, I’m so sorry. I understand what you’re going through, and it’s not easy. Get some help from family and friends.

If you find yourself losing your temper, it’s okay to leave your baby to cry in his crib for a while so you can compose yourself and try again later.

Colic usually goes away by six months, so hold on to the hope that this too shall pass.

5. Too Much Stimulation

Overstimulated Baby Grabbing Face

Have you ever gone to the state fair? Personally, I love the experience. Bright lights, music, rides, and food vendors peddling all kinds of creative (usually fried) snacks.

I’m as extroverted as they come, but by the end of the day I’m exhausted. I just want to have a quiet car ride home and crawl into my bed. My husband, however, is an introvert.

It doesn’t take long before he’s ready to sit down with a giant pretzel and tune out the noise and the crowds.

I know this about him, so I’m happy to take the kids on another ride while he hides away for a while to replenish his energy supply.

Babies can also become overstimulated by lights, noise, people, toys, or just about anything.

Everything is new to them, so the art on the walls, the mobile above their crib, or the sound of siblings playing or the television can quickly become too much.

Since each baby has their own personality, what is fun for one baby can be stressful for another.

If you suspect that your baby may be overstimulated, try taking him to a quiet, dark room. Let him snuggle up in the crook of your neck and block out all of the lights and noise.

If you’re at a loud restaurant or shopping mall you may need to escape outside or pop into a dressing room in a quiet shop.

It may take a few minutes but some close body contact and a quiet environment may do the trick.

6. Boredom

Bored Looking Baby in Crib

Likewise, babies can also become bored or lonely.

As they reach different neurological milestones, they begin to want more interaction with the world around them.

They may only be satisfied if somebody is talking to them, holding them, or actively playing with them. This can be challenging if you’re trying to get ready for work, cook dinner, or help another child.

If you can, take some time to play with your baby. Look at a colorful book or walk around the house flipping light switches or looking in mirrors. Your baby may want to practice standing on your lap or play a game of peek-a-boo. He’ll let you know if he likes something.

But what if you’re occupied and can’t play right now? There are three options.

First, drop what you’re doing and entertain your baby anyway. Weigh the cost. Maybe that laundry can wait, but you might not want to let dinner burn.

Second, enlist the help of your partner or older children in the household to play or read a book with your baby.

Third, finish what you’re doing and allow the baby to cry in a safe place such as a bouncer, play yard, or activity center until you are done.

You may even find that after a few minutes he decides that the toys in front of him are interesting after all!

Try to avoid leaving a baby to cry for an extended period of time, but don’t feel guilty if you just need five minutes alone in the shower, either.

7. Your Baby is Teething

Teething Baby Sucking on Fingers

There’s a lot of variance here, but most babies start teething around six months.

Some babies are overachievers – my son cut his first tooth at only three months old! Meanwhile, my daughter is six months and shows no signs of teeth anywhere in sight, and my friend’s son is a year old with only two teeth.

Common signs of teething include red, swollen gums, lots of drool, chewing on their hands, and extra fussiness.

Cutting a tooth is painful, so be patient with your baby, especially at night when you’re exhausted and your little sleeper turns into a night owl quite suddenly. Some parents explain any fussiness with the explanation, “oh, he’s just teething.”

While it might make you feel better to have an excuse for his cranky behavior, true teething only lasts a few days per tooth. If the gums aren’t red and swollen, then the fussiness is probably due to some other motive.

Once you’ve determined that budding teeth truly are the problem, there are several ways you can help soothe the discomfort.

Some parents dampen a clean washcloth and put it in the freezer for a bit before giving to the baby to gnaw on.

If your baby has begun solids, you can try putting some frozen fruit in a mesh feeder like these from Munchkin and let baby suck and chew on them like a soothing popsicle, or give your baby a silicone teething toy to help them massage their gums as they chew.

Thankfully, after a day or two the tooth will come through and your sweetheart will return to his normal, happy self. Unless of course, there’s another tooth on its way.

8. Your Baby is Uncomfortable

Uncomfortable Newborn Baby Girl Crying

When you are hot, you turn on the fan. When you’re cold, you throw on a sweater. If you have an itch, you scratch it.

Your baby can’t do any of those things and the only way that they can communicate to you that something is wrong is by fussing.

Check your baby’s chest. It should feel warm and dry, and while it is normal for hands and feet to be cooler than the trunk, they should not feel cold. Sometimes all it takes is to add or remove a layer of clothing, or turn on or off a fan to make your baby comfortable.

If your baby doesn’t seem to be hot or cold, check for anything that could be causing discomfort.

It could be a scratchy clothing tag, a diaper that is wet, or a hair twisted around a finger or toe.

If you can’t find anything, try taking all of his clothes off and give him a warm bath and some snuggles.

9. Separation Anxiety

Baby With Separation Anxiety Crying

Somewhere around six months to a year your baby may begin to experience separation anxiety when you leave the room, or even when you are in the same room but somebody else is holding him.

Separation anxiety peaks around 18 months and usually works itself out by 24 months.

Most babies will cry for you so long as they know you can hear them. In all of my years of mothering and working in a nursery and preschool, I have rarely seen a baby cry for more than just a few minutes when their parents left the room.

Thankfully, babies are easily distracted and it doesn’t take long for a caregiver to find a new toy or activity that will cheer your baby up.

It may be tempting to hang around and try to console him, but usually a long, drawn-out goodbye results in a situation that is even more difficult for everyone involved. Neither is it a good idea to sneak out the door and let your little one discover that you’ve gone while they were playing.

While some babies hardly notice, others can be distraught, especially if they have not yet established object permanence: the idea that just because you can’t see something or someone doesn’t mean it no longer exists.

The best course of action is to tell your baby what is going on. Something simple like, “Mommy needs to go now. I’ll be back soon. I love you, bye bye.” Be sure to say “goodbye” and remind them that you will be back.

Even if they are very young, babies can understand more than you think. When you return, be sure to say something like, “see? I told you I would be back.”

Establish this pattern and in time, your baby will learn that even though you have to leave, you will always come back.

10. Developmental Milestones

Baby Development Milestone Chart

Parents often look for physical milestones in their baby, such as rolling over or sitting up. But in addition to these physical changes, your baby’s brain is also growing rapidly.

Your newborn begins to notice objects on the wall or respond to the faces that you make. Soon, he will respond to voices or stare intently at moving shadows in the room.

He will start to understand cause and effect as he bats his hand at toys on the play mat and they swing back and forth.

All of these milestones represent neurological changes, changes which can be distressing as the rules of the outside world seem to be constantly shifting. They need your loving, patient hand to guide them through these milestones.

The book The Wonder Weeks explains in detail common neurological milestones, called “leaps,” and suggests games and activities to keep your baby entertained and progressing through each one.

Read the book one chapter at a time, a week or two before your baby reaches that leap. It’s amazing to see just how quickly they change, sometimes overnight!

Understanding why your baby is extra fussy will help you to be patient through the difficult days (or sometimes weeks!), and you’ll be encouraged as you check off the boxes on the provided checklist and see just how far your little one has progressed.

Wrapping Up

The list I’ve compiled here covers the most common reasons for a fussy baby all of a sudden, but if you’re still stumped, try Baby 411. It’s the closest thing to a manual you can find for baby’s first year.

And remember, if your fussy baby has a fever, hives, rash, diarrhea, or vomiting, be sure to call your doctor.

Even if it’s a false alarm, sometimes we just need a little assurance that everything is okay

Photo of author

Emily Perez

A proud mom of two, Emily is an Educational Consultant with a bachelor's in Education from the University of Texas who specializes in early childhood development.

1 thought on “10 Reasons Why Baby is Suddenly Fussy (PLUS Fast Soothing Tips!)”

  1. Hi

    My grandson whom is live with is 5 months old & have become very grizzly cranky & very irritated for the last 5 days….this is just so not like him, he’s always been so calm & layed back…..can you help or have some idea’s of what could be going on?


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