Lethargic newborn: Is my baby sleepy or sick?
Lethargic newborn: Is my baby sleepy or sick?
Post Author
Post Author
Megan N. Freeland, PharmD
Content Writer
Medically reviewed by
Medically reviewed by
Dr. Marcy Borieux, MD, FAAP
Pediatrician
Dr. Leo Damasco
Pediatrics and Emergency Medicine
Sleepiness is normal for newborns, and they spend most of their day sleeping. But excessive tiredness can also be a sign of illness. So how can you tell if your baby is simply sleepy or truly lethargic? Here’s an overview of what lethargy means, how a lethargic baby might behave, and when it may signal that your baby needs medical attention.
What is lethargy?
A lethargic baby is more than just sleepy. Lethargy means your baby’s energy levels are unusually low, or there’s a noticeable change in their normal alertness or responsiveness. While they may look drowsy, lethargy is different from regular newborn sleepiness.
A lethargic baby may:
Have little or no energy
Be difficult to wake
Seem less alert than usual
Show less awareness of sounds, sights, or surroundings
Lethargy isn’t a condition itself—it’s a symptom. It can be caused by many underlying issues, such as low blood sugar, dehydration, or an infection. Sometimes lethargy develops gradually, which can also make it difficult to recognize.
Difficult to wake
Newborns sleep most of the day, so it’s not always easy to tell normal sleepiness from something more serious. While frequent sleep is expected, your baby should still be alert during their awake times, like looking around, responding to their environment, and feeding well.
If your baby is unusually difficult to wake, sleeps much more than usual, feeds poorly, or seems less responsive even while awake, this may be a sign of lethargy and should be checked by a pediatrician right away. When in doubt, trust your instincts. If you’re worried about your baby’s alertness, seek medical help immediately.
Recognizing a sick newborn
It’s normal for babies to be tired and less active when they’re sick. Lethargy is a red flag when babies are sick. Newborns and young children get sick easily, since they have developing immune systems. Here are signs and symptoms that your baby may be is sick:
Behavior changes: Changes in behavior, aside from lethargy, can occur during illness. Your baby may be restless, irritable, colicky, or hard to soothe. If your baby does not normally behave this way, the behavior change could signal that they’re not feeling well.
Fever: Fever is a telltale sign that your baby’s body is fighting an infection or illness. A fever is a positive sign that your baby’s immune system is doing its job. If your newborn has a fever, seek medical attention immediately. A fever in older infants can be managed with acetaminophen or ibuprofen, depending on their age.
Vomiting: Vomiting can be a sign of a gastrointestinal issue, overheating, or another condition, and it can result in dehydration. If your newborn vomits, they should be seen by a medical professional immediately.
Changes in breathing: Babies have rapid breathing when they are fighting off an infection. The following breathing patterns may be signs of emergency:
Rapid breathing (over 60 breaths in 1 minute)
Nostrils widening or flaring when breathing in
A baby’s chest pulling in around their ribcage or above their collarbones
A baby turning blue or purple
Slowed breathing or prolonged pauses in breathing
Persistent coughing
If you notice these breathing patterns, seek medical attention immediately.
Changes in appetite and dehydration: Babies don’t feed well if they are sick. This can be challenging if your baby is under 6 months old or isn’t eating solids yet, since poor appetite can lead to dehydration. If your newborn is not feeding well or has less wet diapers, contact your local or Summer Health pediatrician.
Cold symptoms: Coughing, a runny nose, or other cold-like symptoms are signs of a respiratory infection. On average, children under 6 years old will have 6 to 8 colds every year and symptoms can last around 10 days. Contact your local or Summer Health pediatrician if your child’s symptoms worsen.
When to consult a pediatrician
Contact a pediatrician if your baby:
Shows changes in breathing, such as rapid, slow, noisy breathing, or pauses in breathing
Has a fever lasting more than 2–3 days
Is not feeding or taking fluids well
Is urinating less often than usual
Appears lethargic, unusually sleepy, or less alert and playful than normal
Is unusually irritable or difficult to soothe
If you have questions about your child’s health, reach out to your local or Summer Health pediatrician for support. Summer Health is a pediatric telehealth platform offering 24/7 care, providing answers for everything from urgent concerns to everyday questions about your child’s health.
Sleepiness is normal for newborns, and they spend most of their day sleeping. But excessive tiredness can also be a sign of illness. So how can you tell if your baby is simply sleepy or truly lethargic? Here’s an overview of what lethargy means, how a lethargic baby might behave, and when it may signal that your baby needs medical attention.
What is lethargy?
A lethargic baby is more than just sleepy. Lethargy means your baby’s energy levels are unusually low, or there’s a noticeable change in their normal alertness or responsiveness. While they may look drowsy, lethargy is different from regular newborn sleepiness.
A lethargic baby may:
Have little or no energy
Be difficult to wake
Seem less alert than usual
Show less awareness of sounds, sights, or surroundings
Lethargy isn’t a condition itself—it’s a symptom. It can be caused by many underlying issues, such as low blood sugar, dehydration, or an infection. Sometimes lethargy develops gradually, which can also make it difficult to recognize.
Difficult to wake
Newborns sleep most of the day, so it’s not always easy to tell normal sleepiness from something more serious. While frequent sleep is expected, your baby should still be alert during their awake times, like looking around, responding to their environment, and feeding well.
If your baby is unusually difficult to wake, sleeps much more than usual, feeds poorly, or seems less responsive even while awake, this may be a sign of lethargy and should be checked by a pediatrician right away. When in doubt, trust your instincts. If you’re worried about your baby’s alertness, seek medical help immediately.
Recognizing a sick newborn
It’s normal for babies to be tired and less active when they’re sick. Lethargy is a red flag when babies are sick. Newborns and young children get sick easily, since they have developing immune systems. Here are signs and symptoms that your baby may be is sick:
Behavior changes: Changes in behavior, aside from lethargy, can occur during illness. Your baby may be restless, irritable, colicky, or hard to soothe. If your baby does not normally behave this way, the behavior change could signal that they’re not feeling well.
Fever: Fever is a telltale sign that your baby’s body is fighting an infection or illness. A fever is a positive sign that your baby’s immune system is doing its job. If your newborn has a fever, seek medical attention immediately. A fever in older infants can be managed with acetaminophen or ibuprofen, depending on their age.
Vomiting: Vomiting can be a sign of a gastrointestinal issue, overheating, or another condition, and it can result in dehydration. If your newborn vomits, they should be seen by a medical professional immediately.
Changes in breathing: Babies have rapid breathing when they are fighting off an infection. The following breathing patterns may be signs of emergency:
Rapid breathing (over 60 breaths in 1 minute)
Nostrils widening or flaring when breathing in
A baby’s chest pulling in around their ribcage or above their collarbones
A baby turning blue or purple
Slowed breathing or prolonged pauses in breathing
Persistent coughing
If you notice these breathing patterns, seek medical attention immediately.
Changes in appetite and dehydration: Babies don’t feed well if they are sick. This can be challenging if your baby is under 6 months old or isn’t eating solids yet, since poor appetite can lead to dehydration. If your newborn is not feeding well or has less wet diapers, contact your local or Summer Health pediatrician.
Cold symptoms: Coughing, a runny nose, or other cold-like symptoms are signs of a respiratory infection. On average, children under 6 years old will have 6 to 8 colds every year and symptoms can last around 10 days. Contact your local or Summer Health pediatrician if your child’s symptoms worsen.
When to consult a pediatrician
Contact a pediatrician if your baby:
Shows changes in breathing, such as rapid, slow, noisy breathing, or pauses in breathing
Has a fever lasting more than 2–3 days
Is not feeding or taking fluids well
Is urinating less often than usual
Appears lethargic, unusually sleepy, or less alert and playful than normal
Is unusually irritable or difficult to soothe
If you have questions about your child’s health, reach out to your local or Summer Health pediatrician for support. Summer Health is a pediatric telehealth platform offering 24/7 care, providing answers for everything from urgent concerns to everyday questions about your child’s health.
Summer Health offers fast and reliable pediatric urgent care through online doctors, all via text. Whether you’re worried about your baby's fever, rashes, or other children's health concerns, we provide expert advice and support anytime, right from your phone.
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