Why is my baby so fussy? Common reasons and when to speak to your doctor.

At some point in every parent's life, usually at 6pm on a Tuesday when you are also trying to cook dinner, your baby becomes inconsolable and you have no idea why. You have fed them. You have burped them. You have offered a nap, a cuddle, a song, a different room. Nothing works. You start to wonder if something is wrong.

Most of the time, nothing is wrong. Babies cry because crying is their only way to communicate, and often the message is some version of "I do not like being this new yet and I need you to help me cope with it."

Here is how to decode it.

The HALT framework: your first checklist

Start with the four things babies get upset about most often. Doctors, nurses, and lactation consultants use a version of this. Ask, in order:

H for Hungry

When did they last eat? Younger babies need to feed every 2 to 3 hours. Growth spurts can shrink that window. If you are not sure, offer the breast or bottle first.

A for Anxious or Overstimulated

Too much noise, too many faces, too bright a room. Babies get overwhelmed quickly, especially when tired. Try a quiet, dim space and slow your own movements down.

L for Lonely or Needing Contact

Babies are biologically wired to be near you. Contact napping, being held, skin-to-skin, even just your voice. This is not a bad habit, it is their neurology.

T for Tired

An overtired baby is the hardest baby to settle. Watch for yawning, ear-pulling, faraway stares, or a sudden burst of activity (this is a stress response, not happiness). If they look tired, get them to sleep now.

HALT catches the vast majority of daily fussiness. If you run through it and nothing fits, move to the second layer.

The second layer: physical discomfort

Babies do not yet know how to tell you what is wrong, so you check for them:

• Wet or dirty diaper. Even a little can be enough to fuss
• Too hot or cold. The back of the neck is the best temperature check
• Clothing. A tag, a thread around a toe, a bunched-up sock
• Gas or wind. Especially after feeds. A gentle tummy massage or bicycle legs can help release it
• Teething. More on this below

The phase factor

Here is the part most baby books skip: your baby's fussiness is often explained by the developmental window they are in.

Around every few weeks in the first year, your baby goes through a burst of cognitive or physical development. Their brain is reorganising. Their body is changing. They are learning something new and big. During these windows, they are often more clingy, more fussy, more tired, and more hungry than usual. When the phase ends, they have a new skill and things settle.

If your baby is around:

• 5 to 6 weeks, they may be in First Smiles
• 8 to 9 weeks, they may be in Discoverer
• 14 to 16 weeks, they may be in The Grabber (and the 4-month sleep regression)
• 23 to 26 weeks, they may be in Rolling / Sitting Up
• 37 to 40 weeks, they may be in The Explorer

These are five of the 35 developmental phases that the Willo App maps out across the first six years. If you know what phase your baby is in, sudden fussiness often becomes much easier to make sense of.

The "witching hour"

Many newborns have a predictable period of fussiness in the late afternoon or early evening, often from around 5pm to 10pm. This is sometimes called the witching hour, though it can last several hours.

It is thought to be caused by a combination of a tired nervous system at the end of the day, dropping melatonin cycles that have not yet stabilised, and sometimes cluster feeding in preparation for a longer night stretch.

There is no fix. There is only survival. Things that help:

• Go outside if you can. A change of environment often resets both of you
• Babywearing. The movement plus closeness soothes many babies
• White noise, womb sounds, or rhythmic motion
• Cluster feeding if your baby wants it
• A warm bath (for baby or both of you together)
• Tagging in a partner or family member. You do not have to do this alone

Witching hours usually resolve around 3 to 4 months as sleep cycles mature.

Teething

Teething typically starts between 4 and 7 months but can begin earlier. Signs include lots of drooling, chewing everything in sight, red cheeks, mild fussiness, and sometimes disturbed sleep. Teething does not usually cause high fevers or severe symptoms. If your baby is very unwell, it is probably not just teething.

Speak to your pediatrician about safe teething remedies appropriate for your baby's age.

When to speak to your pediatrician

Most fussiness is normal. But speak to your pediatrician or family doctor if:

• Your baby is inconsolably crying for more than 3 hours without a clear cause, especially if this is out of character
• Crying is accompanied by fever, vomiting, diarrhoea, a rash, or changes in breathing
• Your baby seems in pain or is pulling up their knees repeatedly
• Feeding has suddenly become very difficult or painful
• Your instinct tells you something is off, even if you cannot name it. Parental instinct is a real clinical signal, and good pediatricians take it seriously
• Your own mental health is suffering. Postpartum anxiety and depression are real, common, and treatable. Please reach out

How the Willo App helps

Inside the Willo App, every baby has a current developmental phase and a set of typical behaviours associated with that window. When your baby is suddenly fussy, you can see at a glance whether it matches what other babies in the same phase are experiencing. Ask Willo is available for real-time questions, and the mood journal helps you spot patterns over a week or a month.

Fussiness often feels random. With a little context, it usually is not.

Common questions

Is it normal for my baby to cry for hours with no reason I can find?

Yes, this happens to almost every baby, especially in the first 3 to 4 months. The "period of PURPLE crying" is a recognised phenomenon that peaks around 6 to 8 weeks. If your baby is otherwise healthy and the crying passes, it is usually normal. If you are concerned, speak to your pediatrician.

Could my baby's fussiness be colic?

Colic is typically defined as crying for more than 3 hours a day, more than 3 days a week, for more than 3 weeks, in an otherwise healthy baby. If this sounds like your situation, speak to your pediatrician. There are strategies that can help.

Does gripe water or gas drops help fussy babies?

These products are commonly used but evidence for their effectiveness is mixed. Always check with your pediatrician before giving your baby any supplement or remedy, especially in the first year.

Is my baby fussy because of something I ate?

Sometimes, if you are breastfeeding. A small number of babies react to dairy, soy, or caffeine in breast milk. If you suspect this, speak to a lactation consultant or pediatrician before making major diet changes.

Will my fussy baby grow out of it?

Yes. The fussiest phase for most babies is 0 to 4 months. By 5 to 6 months, most babies are notably easier to read and settle. Witching hours typically stop by 4 months.

When should I be worried about fussiness?

When it is out of character, very prolonged, accompanied by any illness signs, or your instinct says something is wrong. Always trust that instinct and speak to your pediatrician.