It is 3am. Your baby is making a noise you have not heard before. Or they are very quiet when they should not be. Or they feel hot. Or something just feels wrong and you cannot explain it.
This is the moment every new dad dreads: not knowing whether you are about to overreact and waste everyone's time, or underreact and miss something serious.
This guide cuts through that. It is based on NHS guidelines and covers the symptoms that matter most, organised so you can scan it fast when you need it. No lengthy preambles, no vague reassurances. Just: here is what you are seeing, here is what you do.
How to use this guide: Each section covers a different symptom category. Within each section you will find colour-coded boxes: red means call 999 now, orange means call NHS 111, yellow means contact your GP, green means monitor at home. When in doubt, always call. No paramedic has ever been annoyed at a parent who called for nothing. They would rather that than the alternative.
The Traffic Light System
Before we get into individual symptoms, here is the framework. Every concern fits into one of four responses:
Life-threatening emergency
Do not call NHS 111 first. Do not drive yourself if you are alone with the baby. Call 999 and let them guide you.
Urgent but not immediately life-threatening
NHS 111 is free, available 24/7, and will triage your baby and tell you where to go. Use it. That is what it is for.
Needs professional assessment today or soon
Call the surgery and explain it is a baby. Most practices will prioritise same-day appointments for infants.
Normal or manageable at home
Monitor closely. If anything changes or worsens, reassess and move up the ladder.
With that framework in place, let us go through each major symptom category.
Temperature and Fever
Fever in a young baby is one of the most misunderstood areas for new parents. The age of your baby matters enormously here. The thresholds are not arbitrary. A 2-month-old's immune system is fundamentally different from a 6-month-old's, and the guidelines reflect that.
Normal body temperature for a baby is between 36.4C and 37.4C, measured with a digital thermometer under the armpit. Ear thermometers are unreliable in young babies. Get a digital armpit thermometer and learn to use it before you need it.
Under 3 months old with a temperature of 38C or above
This is a hard rule with no exceptions. A fever in a baby under 3 months can indicate a serious bacterial infection. Their immune system cannot fight it the way an older baby can. Do not give Calpol and wait. Call 999 or go directly to A&E.
3 to 6 months old with a temperature of 39C or above
At this age a high fever still warrants urgent assessment. Call NHS 111 straight away. You can give age-appropriate paracetamol (baby Calpol from 2 months) while you wait for advice, but do not use that as a reason to delay the call.
Over 6 months with a temperature of 38C to 39C
In an older baby, a moderate fever with no other red flag symptoms can wait for a GP assessment. Give age-appropriate paracetamol or ibuprofen (ibuprofen only from 3 months and over 5kg), keep them cool but not cold, and monitor closely. Call NHS 111 if they develop any of the red flag symptoms listed in other sections.
A note on febrile convulsions: Around 1 in 20 children will have a febrile convulsion at some point, usually between 6 months and 3 years. These are seizures triggered by a rapid rise in temperature. They look terrifying: your child may go stiff, shake, go limp, or lose consciousness. If this is the first time it has happened, call 999. Place your baby on their side, do not put anything in their mouth, and time the seizure. Most febrile convulsions stop within 5 minutes and, while frightening, they do not cause brain damage or epilepsy. But the first time it happens, you absolutely need to get medical assessment.
Breathing
Newborns breathe differently to older children and adults. They breathe faster, they occasionally pause for a second or two, and they can sound a bit rattly when they have a slight cold. This is normal and tends to send new parents into a spiral at 2am.
What you are looking for is work of breathing: signs that your baby is having to use extra effort to get air in. Normal breathing is effortless. Laboured breathing is not.
Signs of serious breathing difficulty
- Skin pulling in between the ribs or below the ribcage with each breath (called retractions)
- Nostrils flaring wide with each breath
- A grunting noise at the end of each breath
- Breathing faster than 60 breaths per minute (count for 15 seconds, multiply by 4)
- Any blue or grey tinge around the lips or mouth (cyanosis)
- A pause in breathing lasting more than 20 seconds
Breathing that concerns you but is not yet in crisis
- Consistently faster than normal but no chest retractions
- Wheezing or a high-pitched noise when breathing in (stridor)
- Persistent cough in a baby under 3 months
- Noisy breathing that worsens during feeds or makes feeding difficult
Normal newborn breathing patterns
- Occasional brief pauses of up to 10 seconds (periodic breathing)
- Slight rattling sounds from congestion or mucus
- Breathing at 30 to 60 breaths per minute when calm
- Sneezing frequently (this is how newborns clear their nasal passages, not a sign of a cold)
The Fontanelle (Soft Spot)
The fontanelle is the soft spot on the top of your baby's head where the skull bones have not yet fused. It should feel soft, flat, and slightly pulsing. It is completely normal to see it pulse gently in time with your baby's heartbeat.
What it tells you when it changes is genuinely useful information, so it is worth knowing.
Bulging fontanelle
A fontanelle that is bulging outward, particularly in a baby who is not crying, can indicate increased pressure inside the skull. This could signal meningitis, hydrocephalus, or another serious condition. Do not wait. Call 999 or go to A&E.
Sunken fontanelle
A sunken fontanelle, where the soft spot dips in noticeably, is a sign of dehydration. Look for other dehydration signs alongside it: dry mouth, no tears when crying, no wet nappy in 6 or more hours, sunken eyes, pale or mottled skin. Call NHS 111. Do not try to push fluids yourself without getting guidance first.
What is normal
A fontanelle that pulses gently is normal. It may look slightly sunken when your baby is upright and slightly raised when they cry. The key is what it looks like at rest, when your baby is calm and lying flat. The anterior fontanelle (the big one on top) usually closes between 12 and 18 months.
Feeding and Wet Nappies
A baby who is feeding well and producing wet nappies is, in most cases, doing okay. When those two things stop, it matters.
In the early weeks it can be hard to know if a breastfed baby is getting enough. The nappy count is your best proxy. By day 4 or 5 of life, your baby should have at least 6 heavy wet nappies every 24 hours. Fewer than that is a reason to call your midwife.
Completely unresponsive and not feeding
A newborn who cannot be roused to feed and is floppy or unresponsive is a medical emergency.
Not feeding for 8 or more hours (newborn under 6 weeks)
A newborn who goes 8 or more hours without feeding needs to be assessed. This is not a wait-and-see situation. Call NHS 111 or your community midwife. Newborns need frequent feeds to maintain blood sugar and hydration.
Also call if:
- Your baby has had fewer than 6 wet nappies in 24 hours (after day 5)
- Your baby has not had a dirty nappy in 24 hours in the first month of life
- Breastfeeding has suddenly become very painful and you suspect mastitis or a latch issue
- Your baby is vomiting after every feed and not gaining weight
If you are worried about the mechanics of feeding rather than a medical emergency, a crying and unsettled baby checklist can help you work through possible causes systematically before calling.
Skin Colour
Baby skin colour tells you a lot. Newborns are often blotchy and slightly yellow in the first few days (jaundice is extremely common). But certain colours are a reliable sign that something is wrong.
A note on skin tone: These signs can be harder to spot on darker skin. On brown or black skin, check the palms of the hands, soles of the feet, lips, tongue, and gums for colour changes. A greyish or ashen tone on darker skin is the equivalent of paleness on lighter skin.
Pale, mottled, or blue skin
- Blue or grey tinge around the lips, mouth, or tongue: sign of poor oxygenation. Call 999 immediately.
- Mottled skin (blotchy purple and white pattern across the body): can indicate poor circulation. If combined with high fever, limpness, or any other red flag, call 999.
- Suddenly very pale or grey all over: can indicate shock or serious infection. Call 999.
Yellow-tinged skin (jaundice)
Mild jaundice in the first 2 weeks is common and usually resolves on its own with frequent feeding and indirect daylight. However, you should contact your GP or midwife if:
- Jaundice appears in the first 24 hours of life (this always needs investigation)
- Jaundice spreads to the stomach and legs
- Jaundice has not resolved by 2 weeks (3 weeks in premature babies)
- Your baby's poo is pale, chalky, or white, or their urine is dark yellow
- Your baby is jaundiced and unusually sleepy or difficult to feed
Rashes
Babies get rashes constantly. Most of them are nothing: heat rash, baby acne, erythema toxicum (those tiny red spots with white centres that appear in the first week). But one type of rash is a genuine emergency, and you need to be able to identify it.
A rash that does not fade under pressure (the glass test)
Press a clear glass firmly against the rash. If the spots do not fade, this is a non-blanching rash. It is a potential sign of meningococcal disease or septicaemia. Call 999 immediately.
Do not wait for other symptoms to develop. Do not wait to see if it spreads. Call 999 now and tell them it is a non-blanching rash in an infant.
How to do the glass test: Use a clear drinking glass. Press it firmly against the rash so you can see the skin through the glass. If the rash fades and then returns when you release, that is a blanching rash (usually less concerning). If the spots stay visible through the glass and do not change, that is non-blanching. On darker skin, check areas where the skin is lighter: the soles of the feet, palms, or inside the eyelids.
Other symptoms that often appear alongside meningitis include: high fever, stiff neck or arched back, dislike of bright lights, a high-pitched unusual cry, and a tense or bulging fontanelle. But the rash can appear without any of these.
Rashes that are normal in newborns
- Baby acne: small pimples on the face, appears at 2 to 4 weeks, clears on its own
- Milia: tiny white spots across the nose and cheeks, clears within weeks
- Erythema toxicum: red blotches with white or yellow centres in the first week, harmless
- Heat rash: small red spots in skin folds when overheated
- Cradle cap: crusty, yellowish patches on the scalp, harmless and usually clears by 12 months
If a rash looks infected (oozing, crusting, spreading from a specific wound) or is combined with fever, call NHS 111.
Drowsiness and Responsiveness
Newborns sleep a lot. 16 to 18 hours a day is completely normal. The question is not whether your baby is sleeping, it is whether you can rouse them when you try.
Floppy, limp, or will not wake up
- Baby is unusually limp when you pick them up (low muscle tone)
- Baby will not wake up when you try, even with gentle stimulation
- Baby is unresponsive or not reacting to you at all
- Baby feels like a rag doll when held (no resistance, head flopping)
Unusually difficult to rouse or very unlike themselves
If your baby is much harder than usual to wake for feeds, or is awake but completely uninterested and not engaging, this is worth a call to NHS 111 especially if combined with any other symptom on this page.
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Get The New Dad PlaybookCrying
Crying is a baby's primary communication tool. Most crying has a cause: hunger, wind, discomfort, overstimulation, tiredness. Working through the most likely causes first is sensible. But some crying patterns warrant more than a nappy change.
A high-pitched, unusual, continuous cry
If your baby has a cry that sounds completely different to their normal cry, particularly a high-pitched, shrill, weak, or whimpering cry that will not stop, this can be a sign of neurological distress or pain. Call 999 especially if combined with fever, fontanelle changes, or difficulty waking.
Prolonged crying with no identifiable cause
If your baby cries for more than 3 hours and you cannot settle them and cannot find an obvious cause, it is reasonable to call your GP or midwife for advice. It may well be colic (which peaks around 6 weeks and usually resolves by 3 to 4 months). But it is worth checking, especially if this is a new pattern.
For a methodical approach to working out why your baby is crying, the Why Is My Baby Crying guide walks through each likely cause in order.
Vomiting and Diarrhoea
Posseting, which is bringing up a small amount of milk after feeding, is completely normal. Proper vomiting is different: it is forceful, there is a lot of it, and it happens repeatedly.
Projectile vomiting in a baby under 8 weeks
Forceful, projectile vomiting after every feed in a young baby, particularly in a baby who is always hungry and losing weight, is a potential sign of pyloric stenosis (a narrowing of the stomach outlet). This needs urgent surgical assessment. Go to A&E.
Also go to A&E if the vomit contains bile (green), blood, or looks like coffee grounds.
Repeated vomiting or diarrhoea with signs of dehydration
If your baby has vomited more than twice and is showing signs of dehydration (sunken fontanelle, no wet nappies, dry mouth, sunken eyes), call NHS 111. Infants dehydrate much faster than adults.
Diarrhoea in babies can be hard to spot because newborn poo is already quite liquid. What you are looking for is a change: more frequent, more watery, and possibly foul-smelling compared to their normal. More than 6 watery stools in 24 hours warrants a call to NHS 111, especially if combined with vomiting or reduced feeding.
Seizures and Convulsions
Seeing your baby have a seizure is one of the most frightening things a parent can experience. Knowing what to do and what not to do matters.
Any seizure in a baby
- Rhythmic jerking or twitching of limbs, face, or body
- Sudden stiffening of the whole body
- Eyes rolling back or fixed staring
- Breathing stops or becomes irregular during the episode
- Baby goes blue during the episode
What to do: Place your baby on their side on a safe, flat surface. Do not put anything in their mouth. Do not try to restrain them. Time the seizure from when it starts. Call 999 and stay on the line.
What not to do: Do not try to cool a feverish baby with cold water during a seizure. Do not pick them up and move them unless they are in immediate danger. Do not try to force-feed them anything.
Neonatal seizures (in the first 28 days of life) can look subtle and different from seizures in older babies. Lip smacking, cycling leg movements, or sudden repeated eye blinking can all be seizure activity. If you notice anything like this, video it on your phone if you can (this is hugely helpful for doctors) and call 999.
The Gut Check
Here is the thing about parenting a newborn: your instincts are calibrating in real time. The first few weeks you will second-guess everything. By month two you will know your baby's normal, and deviation from that normal will set off an alarm in your gut before you can name what is wrong.
That gut alarm is legitimate data. If something feels wrong, act. The NHS 111 line is specifically designed for this. You are not wasting anyone's time. You are being a good parent.
"If you are worried about your baby, trust your instincts and seek medical help. It is always better to check and be reassured than to wait." - NHS
The anxiety that comes with a new baby is real and it is normal. If you find yourself spiralling in the small hours, the New Dad Anxiety guide covers that specifically, including why it spikes at night and what actually helps.
Quick Reference: When to Act
Bookmark this section. This is what you scan at 3am.
- Under 3 months with a temperature of 38C or above
- Difficulty breathing: retractions, grunting, blue lips, breathing over 60/min
- Non-blanching rash (does not fade under a glass)
- Bulging fontanelle when not crying
- Floppy, limp, unresponsive baby
- High-pitched, shrill, continuous cry that is nothing like their usual cry
- Bile (green) or blood in vomit
- Blue or grey skin around the mouth
- Any seizure, fit, or convulsion
- Breathing pause lasting more than 20 seconds
- 3 to 6 months with a temperature of 39C or above
- Newborn not fed for 8 or more hours
- Fewer than 6 wet nappies in 24 hours (after day 5 of life)
- Sunken fontanelle with other dehydration signs
- Breathing faster than usual but no retractions
- Repeated vomiting or diarrhoea with dehydration signs
- Baby much harder to rouse than normal
- Projectile vomiting after every feed (under 8 weeks)
- Over 6 months with temperature of 38C to 39C
- Crying for more than 3 hours with no identifiable cause
- Jaundice not resolving by 2 weeks
- Persistent rash that looks infected (oozing, spreading)
- Any symptom that concerns you but does not warrant 999 or 111
- Occasional brief breathing pauses under 10 seconds
- Normal newborn rashes (baby acne, milia, erythema toxicum)
- Posseting small amounts of milk after feeds
- Mild jaundice in days 2 to 14 with normal feeding and nappy output
- Frequent sneezing (normal nasal clearing)
Frequently Asked Questions
What temperature is a fever in a baby under 3 months?
Any temperature of 38C or above in a baby under 3 months is a medical emergency. Call 999 or go to A&E immediately. Do not wait to see if it comes down.
When should I take my baby to hospital for a rash?
If your baby has a rash that does not fade when you press a glass against it, this could be a sign of meningococcal disease. Call 999 immediately. Do not wait for other symptoms to develop.
How long can a newborn go without feeding before I need to worry?
A newborn who has not fed for 8 or more hours needs to be seen by a doctor. Call NHS 111 or your midwife. Newborns need to feed frequently to avoid dehydration and low blood sugar.
What does a sunken fontanelle mean?
A sunken fontanelle (the soft spot on your baby's head) is a sign of dehydration. If combined with other signs like dry mouth, no wet nappies, or sunken eyes, call NHS 111 or go to A&E urgently.
What does laboured breathing look like in a baby?
Signs of laboured breathing include: the skin between or below the ribs pulling in with each breath, nostrils flaring, a grunting sound with each exhale, breathing faster than 60 breaths per minute, or any blue tinge around the lips. Call 999 if you see these signs.
What should I do if my baby has a seizure or febrile convulsion?
If your baby has a seizure for the first time, call 999 immediately. Place them on their side, do not put anything in their mouth, and time the seizure. Febrile convulsions are triggered by rapid temperature changes and affect 1 in 20 children. They look terrifying but are usually not dangerous. Always get medical assessment after a first seizure.
For more on managing those first chaotic weeks, the Newborn Sleep Schedule and How to Hold a Newborn guides cover the basics every new dad needs.
