Why Is My Baby So Fussy All of a Sudden at 4 Weeks?

The 4-week fussiness: totally normal (but exhausting)

You're four weeks in, you're finally getting the hang of things… and then boom: your sweet little baby turns into a cranky, clingy, non-stop crying machine. Totally out of nowhere, right?
Yeah. We've all been there.

Before you panic or blame yourself (please don’t), know this: it’s very common for babies to hit a fussy patch right around 4 weeks old. There are reasons behind it, even if they’re not always super obvious in the moment.

Let’s break it down.

Growth spurts and developmental leaps

Your baby is growing (literally)

At 4 weeks, many babies go through a growth spurt. That means:

• They're hungrier than usual

• They want to nurse/feed more frequently (cluster feeding, anyone?)

• They wake more often

• And yes… they cry. A lot.

Their little bodies are doing a ton of work behind the scenes — building muscle, stretching out, developing the nervous system. Imagine your whole body changing by the hour — yeah, you'd be fussy too.

The first “wonder week”

Some experts (like in the Wonder Weeks theory) describe a mental leap happening around this age. Babies start noticing the world in a new way — light, sound, distance, textures. It’s like a sensory overload, and they don’t yet know how to process it.

They may suddenly want to be held all the time, or have trouble falling asleep. Basically: their brain is leveling up, and it’s a bit much.

Is it colic? Maybe… but maybe not

What colic looks like

Colic is usually defined as:

• Crying for 3+ hours a day

• For 3+ days a week

• For 3+ weeks in a row

And it usually starts around week 3 or 4. If your baby’s screaming seems non-stop and nothing calms them, it might be colic. But honestly? That term is kinda vague and still debated.

Some doctors now believe what we call “colic” is often just normal baby behavior combined with digestive immaturity.

Gas and tummy troubles

This one’s classic: baby gets fussy after feeds, pulls legs up, makes grunty noises. It could be:

• Gas

• Reflux

• Overfeeding or underfeeding

• Sensitivity to formula (or something in your diet if you’re breastfeeding)

Try some gentle tummy massage or bicycle legs. Burping mid-feed can also help.

I remember my daughter at 4 weeks — every evening around 7 p.m., she'd go full drama queen, flailing and wailing like we ruined her life. Turned out she just needed to fart. A tiny burp and boom: angel again.

The “witching hour” is real

It’s a thing. Late afternoon to early evening (usually between 5–10 p.m.) is prime time for fussiness, especially at this age.
Why? No one really knows. But it might be:

• Baby overstimulation

• Fatigue

• Hunger catching up

• Your own stress rubbing off on baby

Honestly, sometimes nothing “fixes” it — you just get through it. Babywearing, rocking, warm baths… try different things and see what helps. And remember: you’re not doing anything wrong.

When should I worry?

Okay, so when is fussiness not normal? Call your pediatrician if:

• Your baby has a fever (anything over 100.4°F / 38°C for babies under 3 months)

• There's a sudden change in appetite (not eating at all)

• Baby seems lethargic or hard to wake

• You suspect pain (like constant crying without break, arching back, etc.)

Most of the time, though, the 4-week fussiness is just a phase. It passes (even if it feels eternal while you're in it).

Final thoughts: You’re not alone, and it won’t last forever

Four weeks is a milestone — for your baby and for you. Their world is expanding fast, and yeah, it’s overwhelming. For both of you.

But this sudden fussiness? It’s not your fault. It doesn’t mean your baby is “broken” or that you’re doing anything wrong.

Breathe. Ask for help. Take turns with your partner. Or put baby down somewhere safe and step away for a few minutes if you need to. That’s not selfish — it’s smart.

And just remember: this too shall pass.

Is 165 cm normal for a 15 year old?

The predicted height for a female, based on your parents heights, is 155 to 165cm. Most 15 year old girls are nearly done growing. I was too. It's a very normal height for a girl.

Is 160 cm too tall for a 12 year old?

How Tall Should a 12 Year Old Be? We can only speak to national average heights here in North America, whereby, a 12 year old girl would be between 137 cm to 162 cm tall (4-1/2 to 5-1/3 feet). A 12 year old boy should be between 137 cm to 160 cm tall (4-1/2 to 5-1/4 feet).

How tall is a average 15 year old?

Average Height to Weight for Teenage Boys - 13 to 20 Years

How to get taller at 18?

Staying physically active is even more essential from childhood to grow and improve overall health. But taking it up even in adulthood can help you add a few inches to your height. Strength-building exercises, yoga, jumping rope, and biking all can help to increase your flexibility and grow a few inches taller.

Is 5.7 a good height for a 15 year old boy?

Generally speaking, the average height for 15 year olds girls is 62.9 inches (or 159.7 cm). On the other hand, teen boys at the age of 15 have a much higher average height, which is 67.0 inches (or 170.1 cm).

Can you grow between 16 and 18?

Most girls stop growing taller by age 14 or 15. However, after their early teenage growth spurt, boys continue gaining height at a gradual pace until around 18. Note that some kids will stop growing earlier and others may keep growing a year or two more.

Can you grow 1 cm after 17?

Even with a healthy diet, most people's height won't increase after age 18 to 20. The graph below shows the rate of growth from birth to age 20. As you can see, the growth lines fall to zero between ages 18 and 20 ( 7 , 8 ). The reason why your height stops increasing is your bones, specifically your growth plates.