When to Call the Pediatrician: Fever, Breathing Changes & Nighttime Red Flags for Newborns

Quick overview: why fast action matters

Newborns (especially under 3 months) can become seriously ill very quickly and often don’t show the same clear symptoms older children do. This guide summarizes the most important fever, breathing and nighttime red flags, plus immediate steps you can take and when to call your pediatrician or emergency services.

Key rule: if your baby is 3 months old or younger and has a measured rectal temperature of 100.4°F (38.0°C) or higher, contact your pediatrician (or go to the emergency department) immediately for evaluation.

Fever: how to measure it and when to act

What counts as a fever: a rectal temperature of 100.4°F (38°C) or higher is considered a fever in infants, and rectal measurement is the most reliable method for babies under 3 months. If you use axillary (underarm) or forehead thermometers, results can be less accurate and your clinician may want confirmation with a rectal reading.

When to call now

• Any baby 3 months or younger with a rectal temp ≥100.4°F (38°C): call your pediatrician or go to the ER immediately.
• Babies 3–6 months with fever around or above 101°F (38.3°C), or any infant who looks unusually ill, should be evaluated promptly.

What to do before you go

• Take and record the exact temperature, note how you measured it (rectal, axillary, temporal), and the time.
• Keep the baby comfortable and hydrated. Don’t bundle them in heavy blankets if they feel warm.
• Do not give aspirin. For very young infants (generally under ~3 months), do not give fever medicine without your provider’s instruction. Ask the on-call pediatrician for dosing guidance if medications are advised.

Breathing changes and color: emergency signs to watch for

Breathing and color changes in a newborn can be signs of respiratory distress or low oxygen. Normal newborn respiratory rate is roughly 30–60 breaths per minute; persistent rates above about 60 breaths/min (especially with other signs) are concerning.

Red flags that need immediate attention

• Grunting with each breath, nasal flaring, or noticeable retractions (skin sucking in around ribs or sternum) — these are signs the baby is working hard to breathe.
• Blue or gray color around the lips, face, or body (central cyanosis) — call 911 or go to the nearest ER now.
• Long pauses in breathing (apnea) lasting more than 10–20 seconds, or repeated pauses with color change or limpness.
• Very fast breathing (>60 breaths/min) accompanied by poor feeding, lethargy, or temperature changes.

If you see any of the above, call emergency services or go to the nearest emergency department immediately; if in doubt, treat breathing difficulty or color change as an emergency.

Nighttime red flags, feeding, urine output and what to do

Many newborn issues first appear at night. Know these red flags that should prompt you to call now: persistent high fever in a very young infant, difficulty breathing, blue or mottled color, severe lethargy or poor responsiveness (hard to wake), repeated vomiting, or seizure activity. If the baby is unresponsive or you think their life is at risk, call 911.

Feeding and urine cues

Wet-diapier and feeding patterns help indicate hydration and intake. After the first few days, expect about 4–6 wet diapers per 24 hours by day 4–5 and typically 6–8 wet diapers daily once feeding is well established. Significantly fewer wet diapers, sunken eyes or a dry mouth can indicate dehydration and need prompt evaluation.

Practical steps to take at night

1. Stay calm and quickly assess airway, breathing and color. If baby is not breathing or is blue and limp, call 911 and begin infant CPR if trained.
2. Measure and record temperature (note method), count respirations for a full minute while baby is calm, and check how many wet diapers in the past 24 hours.
3. If symptoms are concerning but not an immediate emergency (e.g., fever in older infant without severe signs, decreased feeding but baby arousable), call your pediatrician’s on-call number. Many practices triage by phone and can tell you whether to come in or go to the ER.
4. If a provider advises medication and your baby is old enough, follow specific dosing instructions; do not give ibuprofen to infants under 6 months or give any medication to very young infants without medical direction.

Keep important contacts visible (pediatrician on-call, nearest ER, poison control 1-800-222-1222) and a digital thermometer handy. When in doubt, call — pediatric offices expect and triage calls about newborns, especially at night.

Bottom line: For newborns, err on the side of caution — any fever at or above 100.4°F in babies 3 months or younger, breathing distress, color change, poor feeding or markedly decreased wet diapers should trigger immediate contact with your pediatrician or emergency services. Being prepared and knowing these red flags can make a critical difference.