Medical Conditions

Congenital Hyperinsulinism - Persistent Low Blood Sugar in My Baby

Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist

Content reviewed against published AAP, NIH, Children's Hospital of Philadelphia guidelines

Editorial policy

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If your baby has been diagnosed with or you suspect congenital hyperinsulinism - persistent low blood sugar in my baby, here is what the evidence says.

The short answer

Congenital hyperinsulinism (CHI) is the most common cause of persistent and severe low blood sugar (hypoglycemia) in newborns and infants. The pancreas produces too much insulin, causing blood sugar to drop dangerously low. Signs include jitteriness, seizures, poor feeding, lethargy, and episodes of limpness or unresponsiveness. CHI requires urgent diagnosis and treatment because prolonged low blood sugar can cause permanent brain damage. Treatment may include medications (diazoxide, octreotide) or surgery depending on the type.

Key takeaways

  • Congenital hyperinsulinism (CHI) is the most common cause of persistent and severe low blood sugar (hypoglycemia) in newborns and infants. The pancreas produces too much insulin, causing blood sugar to drop dangerously low. Signs include jitteriness, seizures, poor feeding, lethargy, and episodes of limpness or unresponsiveness. CHI requires urgent diagnosis and treatment because prolonged low blood sugar can cause permanent brain damage. Treatment may include medications (diazoxide, octreotide) or surgery depending on the type.
  • Usually normal when: Mild blood sugar dips in the first 24-48 hours of life that respond to feeding and resolve by day 2-3
  • Call your doctor if: Your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care
  • Varies by age — see the age-by-age breakdown below
“Fever itself is not an illness — rather, it is a sign or symptom that the body is fighting an infection. Fever stimulates certain defenses, such as the white blood cells, which attack and destroy invading bacteria.”
— Fever and Your Child, American Academy of Pediatrics (AAP)

This is one of the most common questions parents ask. Searching for answers means you care.

What Parents Should Know

According to AAP, NIH, Children's Hospital of Philadelphia guidelines, congenital hyperinsulinism (CHI) is the most common cause of persistent and severe low blood sugar (hypoglycemia) in newborns and infants. The pancreas produces too much insulin, causing blood sugar to drop dangerously low. Signs include jitteriness, seizures, poor feeding, lethargy, and episodes of limpness or unresponsiveness. CHI requires urgent diagnosis and treatment because prolonged low blood sugar can cause permanent brain damage. Treatment may include medications (diazoxide, octreotide) or surgery depending on the type. At 0-48 hours, many babies have transiently low blood sugar in the first 24-48 hours of life, especially if they are large for gestational age, born to mothers with diabetes, premature, or stressed during delivery. This transient hypoglycemia usually resolves with feeding. However, if blood sugar remains persistently low despite feeding, requires IV glucose to maintain normal levels, or is very low (below 40 mg/dL), congenital hyperinsulinism should be considered. A critical sample (blood drawn during a low blood sugar episode) measuring insulin, cortisol, growth hormone, and free fatty acids helps establish the diagnosis. It is generally considered normal when mild blood sugar dips in the first 24-48 hours of life that respond to feeding and resolve by day 2-3. However, you should contact your pediatrician promptly if your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care.

Sources: [1], [2], [3]

Normal vs. Concerning

Usually Normal
Worth Discussing
Mild blood sugar dips in the first 24-48 hours of life that respond to feeding and resolve by day 2-3
Your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care
Blood sugar levels that remain above 50 mg/dL after the first 48 hours with normal feeding
Your baby in the hospital requires increasingly high amounts of IV glucose to maintain normal blood sugar, suggesting congenital hyperinsulinism that needs specialist evaluation
A single low blood sugar reading in an otherwise well newborn that normalizes and does not recur
Your child with known CHI becomes ill with vomiting or refuses to eat, which can precipitate life-threatening hypoglycemia requiring emergency management
Brief jitteriness in a newborn that resolves with feeding and does not recur
Your baby seems unusually sleepy, difficult to arouse for feeds, or has trembling or jitteriness that recurs

When to Seek Immediate Care

  • Your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care
  • Your baby in the hospital requires increasingly high amounts of IV glucose to maintain normal blood sugar, suggesting congenital hyperinsulinism that needs specialist evaluation
  • Your child with known CHI becomes ill with vomiting or refuses to eat, which can precipitate life-threatening hypoglycemia requiring emergency management

By Age

What to expect by age

0-48 hours

Many babies have transiently low blood sugar in the first 24-48 hours of life, especially if they are large for gestational age, born to mothers with diabetes, premature, or stressed during delivery. This transient hypoglycemia usually resolves with feeding. However, if blood sugar remains persistently low despite feeding, requires IV glucose to maintain normal levels, or is very low (below 40 mg/dL), congenital hyperinsulinism should be considered. A critical sample (blood drawn during a low blood sugar episode) measuring insulin, cortisol, growth hormone, and free fatty acids helps establish the diagnosis.

2 days - 3 months

CHI typically presents within the first few days to weeks of life. Affected babies may have seizures, episodes of limpness or unresponsiveness, excessive sleepiness, poor feeding, or jitteriness. They often require high glucose infusion rates (greater than 8 mg/kg/min) through an IV to maintain normal blood sugar. Babies may be large for gestational age at birth due to the growth-promoting effects of excess insulin in utero. Diagnosis is confirmed by demonstrating inappropriately elevated insulin levels during hypoglycemia. Genetic testing can identify the specific mutation and guide treatment.

3-12 months

Some milder forms of CHI may not present until the baby starts going longer between feedings or during illnesses when food intake decreases. Parents may notice the baby is unusually sleepy, irritable, or has episodes of staring or trembling. Focal forms of CHI (where only part of the pancreas is affected) can be identified with a specialized PET scan and may be cured with surgery. Diffuse forms (the entire pancreas is affected) are typically managed with medications first, and surgery is considered if medications fail.

1-3 years

Some children with milder forms of CHI may not be diagnosed until toddlerhood, particularly if they present with seizures or developmental delays from unrecognized hypoglycemia. In children on treatment, careful management during illness is essential because fasting or vomiting can precipitate dangerous hypoglycemia. Some children with CHI may eventually outgrow their hypoglycemia as the pancreas matures, particularly those with certain genetic mutations. Long-term monitoring of neurodevelopment is important.

What to Tell Your Pediatrician

  • Describe when you first noticed congenital hyperinsulinism - persistent low blood sugar in my baby and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby seems unusually sleepy, difficult to arouse for feeds, or has trembling or jitteriness that recurs.
  • Mention if your baby has had more than one episode of low blood sugar that required intervention.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...
  • Mild blood sugar dips in the first 24-48 hours of life that respond to feeding and resolve by day 2-3
  • Blood sugar levels that remain above 50 mg/dL after the first 48 hours with normal feeding
  • A single low blood sugar reading in an otherwise well newborn that normalizes and does not recur
  • Brief jitteriness in a newborn that resolves with feeding and does not recur
Mention at your next visit when...
  • Your baby seems unusually sleepy, difficult to arouse for feeds, or has trembling or jitteriness that recurs
  • Your baby has had more than one episode of low blood sugar that required intervention
  • Your baby is large for gestational age and seems to have difficulty maintaining blood sugar between feeds
Act now when...
  • Your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care
  • Your baby in the hospital requires increasingly high amounts of IV glucose to maintain normal blood sugar, suggesting congenital hyperinsulinism that needs specialist evaluation
  • Your child with known CHI becomes ill with vomiting or refuses to eat, which can precipitate life-threatening hypoglycemia requiring emergency management

What You Can Do at Home

  • Keep track of when you notice congenital hyperinsulinism - persistent low blood sugar in my baby — noting the time of day, duration, and any triggers can help your pediatrician.
  • Remember that mild blood sugar dips in the first 24-48 hours of life that respond to feeding and resolve by day 2-3 — this is generally within the range of normal.
  • At 0-48 hours, focus on observation rather than intervention unless your pediatrician advises otherwise.
  • Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
  • While monitoring at home, seek immediate care if your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care.

Type 1 Diabetes Signs in My Toddler

Type 1 diabetes in toddlers can present with excessive thirst (polydipsia), frequent urination (polyuria), unexplained weight loss, increased appetite, irritability, and fatigue. Because toddlers are still in diapers, the increased urination may be noticed as unusually heavy or more frequent wet diapers. Type 1 diabetes requires urgent medical attention because it can rapidly progress to diabetic ketoacidosis (DKA), a life-threatening emergency.

Congenital Hypothyroidism in Babies

Congenital hypothyroidism occurs when a baby is born with an underactive or absent thyroid gland, affecting about 1 in 2,000 to 4,000 newborns. Thanks to universal newborn screening, most cases are detected within days of birth before symptoms develop. When treated promptly with daily thyroid hormone medication, children develop normally with no intellectual impairment.

My Baby's Newborn Screening Flagged Congenital Adrenal Hyperplasia (CAH)

Congenital adrenal hyperplasia (CAH) is a group of genetic conditions affecting the adrenal glands' ability to produce cortisol and sometimes aldosterone. The most common form (21-hydroxylase deficiency) affects about 1 in 15,000 births. In severe (classic) forms, the body cannot make enough cortisol to respond to stress and may not properly regulate salt balance. CAH is detected on newborn screening in most states. With appropriate hormone replacement therapy, children with CAH grow up healthy and active. The key is consistent medication, stress dosing during illness, and regular follow-up with a pediatric endocrinologist.

Growth Hormone Deficiency Signs

Growth hormone deficiency (GHD) occurs when the pituitary gland does not produce enough growth hormone to support normal growth. It affects approximately 1 in 4,000-10,000 children. In babies, it may present with low blood sugar (hypoglycemia), prolonged jaundice, small genitalia in boys, or slow linear growth. In older infants and toddlers, the hallmark sign is a progressively declining growth velocity, causing the child to fall farther behind peers on the growth chart. GHD is treatable with daily growth hormone injections, and early treatment leads to better outcomes.

Milestone

Month-by-Month Development

Detailed monthly development guides from birth through 24 months.

Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is congenital hyperinsulinism - persistent low blood sugar in my baby normal?
Congenital hyperinsulinism (CHI) is the most common cause of persistent and severe low blood sugar (hypoglycemia) in newborns and infants. The pancreas produces too much insulin, causing blood sugar to drop dangerously low. Signs include jitteriness, seizures, poor feeding, lethargy, and episodes of limpness or unresponsiveness. CHI requires urgent diagnosis and treatment because prolonged low blood sugar can cause permanent brain damage. Treatment may include medications (diazoxide, octreotide) or surgery depending on the type.
When should I call the doctor about congenital hyperinsulinism - persistent low blood sugar in my baby?
Your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care Your baby in the hospital requires increasingly high amounts of IV glucose to maintain normal blood sugar, suggesting congenital hyperinsulinism that needs specialist evaluation Your child with known CHI becomes ill with vomiting or refuses to eat, which can precipitate life-threatening hypoglycemia requiring emergency management
When is congenital hyperinsulinism - persistent low blood sugar in my baby normal?
Mild blood sugar dips in the first 24-48 hours of life that respond to feeding and resolve by day 2-3 Blood sugar levels that remain above 50 mg/dL after the first 48 hours with normal feeding A single low blood sugar reading in an otherwise well newborn that normalizes and does not recur
What causes congenital hyperinsulinism - persistent low blood sugar in my baby?
Congenital hyperinsulinism (CHI) is the most common cause of persistent and severe low blood sugar (hypoglycemia) in newborns and infants. The pancreas produces too much insulin, causing blood sugar to drop dangerously low. Signs include jitteriness, seizures, poor feeding, lethargy, and episodes of limpness or unresponsiveness. CHI requires urgent diagnosis and treatment because prolonged low blood sugar can cause permanent brain damage. Treatment may include medications (diazoxide, octreotide) or surgery depending on the type. Common explanations include: Mild blood sugar dips in the first 24-48 hours of life that respond to feeding and resolve by day 2-3. Blood sugar levels that remain above 50 mg/dL after the first 48 hours with normal feeding.
What should I mention to my pediatrician about congenital hyperinsulinism - persistent low blood sugar in my baby?
You should mention congenital hyperinsulinism - persistent low blood sugar in my baby at your next visit if: Your baby seems unusually sleepy, difficult to arouse for feeds, or has trembling or jitteriness that recurs. Your baby has had more than one episode of low blood sugar that required intervention. Your baby is large for gestational age and seems to have difficulty maintaining blood sugar between feeds.
Is congenital hyperinsulinism - persistent low blood sugar in my baby normal at 0-48 hours?
Many babies have transiently low blood sugar in the first 24-48 hours of life, especially if they are large for gestational age, born to mothers with diabetes, premature, or stressed during delivery. This transient hypoglycemia usually resolves with feeding. However, if blood sugar remains persistently low despite feeding, requires IV glucose to maintain normal levels, or is very low (below 40 mg/dL), congenital hyperinsulinism should be considered. A critical sample (blood drawn during a low blood sugar episode) measuring insulin, cortisol, growth hormone, and free fatty acids helps establish the diagnosis.
Is congenital hyperinsulinism - persistent low blood sugar in my baby normal at 2 days - 3 months?
CHI typically presents within the first few days to weeks of life. Affected babies may have seizures, episodes of limpness or unresponsiveness, excessive sleepiness, poor feeding, or jitteriness. They often require high glucose infusion rates (greater than 8 mg/kg/min) through an IV to maintain normal blood sugar. Babies may be large for gestational age at birth due to the growth-promoting effects of excess insulin in utero. Diagnosis is confirmed by demonstrating inappropriately elevated insulin levels during hypoglycemia. Genetic testing can identify the specific mutation and guide treatment.
Should I go to the ER for congenital hyperinsulinism - persistent low blood sugar in my baby?
Seek emergency care if your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care, or if your baby in the hospital requires increasingly high amounts of IV glucose to maintain normal blood sugar, suggesting congenital hyperinsulinism that needs specialist evaluation. When in doubt, call your pediatrician's after-hours line for guidance.
Does congenital hyperinsulinism - persistent low blood sugar in my baby go away on its own?
In many cases, congenital hyperinsulinism - persistent low blood sugar in my baby resolves on its own, especially when mild blood sugar dips in the first 24-48 hours of life that respond to feeding and resolve by day 2-3. By 1-3 years, some children with milder forms of CHI may not be diagnosed until toddlerhood, particularly if they present with seizures or developmental delays from unrecognized hypoglycemia. In children on treatment, careful management during illness is essential because fasting or vomiting can precipitate dangerous hypoglycemia. Some children with CHI may eventually outgrow their hypoglycemia as the pancreas matures, particularly those with certain genetic mutations. Long-term monitoring of neurodevelopment is important.
AAPNIHCHILDREN'S HOSPITAL OF PHILADELPHIA

References

  1. [1]Thornton PS, Stanley CA, De Leon DD, et al. Recommendations from the Pediatric Endocrine Society for Evaluation and Management of Persistent Hypoglycemia in Neonates, Infants, and Children. Journal of Pediatrics. 2015;167(2):238-245. AAP
  2. [2]National Organization for Rare Disorders (NORD). Congenital Hyperinsulinism. NIH
  3. [3]Children's Hospital of Philadelphia. Congenital Hyperinsulinism Center. Diagnosis and Treatment of Congenital Hyperinsulinism. Children's Hospital of Philadelphia

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Congenital Hyperinsulinism - Persistent Low Blood Sugar in My Baby.

Things to mention

  • Describe when you first noticed congenital hyperinsulinism - persistent low blood sugar in my baby and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby seems unusually sleepy, difficult to arouse for feeds, or has trembling or jitteriness that recurs.
  • Mention if your baby has had more than one episode of low blood sugar that required intervention.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

  • Your baby seems unusually sleepy, difficult to arouse for feeds, or has trembling or jitteriness that recurs
  • Your baby has had more than one episode of low blood sugar that required intervention
  • Your baby is large for gestational age and seems to have difficulty maintaining blood sugar between feeds

Urgent signs to report immediately

  • Your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care
  • Your baby in the hospital requires increasingly high amounts of IV glucose to maintain normal blood sugar, suggesting congenital hyperinsulinism that needs specialist evaluation
  • Your child with known CHI becomes ill with vomiting or refuses to eat, which can precipitate life-threatening hypoglycemia requiring emergency management

My notes

From ismybabyalright.com — free, evidence-based baby health guides

All content follows our editorial policy and is reviewed against published clinical guidelines.

2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members

Related Resources

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Bottom line

Most cases of congenital hyperinsulinism - persistent low blood sugar in my baby are normal. Talk to your pediatrician if your baby has a seizure, becomes limp and unresponsive, or is impossible to wake up, as these may be signs of dangerously low blood sugar requiring emergency care.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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Type 1 diabetes in toddlers can present with excessive thirst (polydipsia), frequent urination (polyuria), unexplained weight loss, increased appetite, irritability, and fatigue. Because toddlers are still in diapers, the increased urination may be noticed as unusually heavy or more frequent wet diapers. Type 1 diabetes requires urgent medical attention because it can rapidly progress to diabetic ketoacidosis (DKA), a life-threatening emergency.

Congenital Hypothyroidism in Babies

Congenital hypothyroidism occurs when a baby is born with an underactive or absent thyroid gland, affecting about 1 in 2,000 to 4,000 newborns. Thanks to universal newborn screening, most cases are detected within days of birth before symptoms develop. When treated promptly with daily thyroid hormone medication, children develop normally with no intellectual impairment.

My Baby's Newborn Screening Flagged Congenital Adrenal Hyperplasia (CAH)

Congenital adrenal hyperplasia (CAH) is a group of genetic conditions affecting the adrenal glands' ability to produce cortisol and sometimes aldosterone. The most common form (21-hydroxylase deficiency) affects about 1 in 15,000 births. In severe (classic) forms, the body cannot make enough cortisol to respond to stress and may not properly regulate salt balance. CAH is detected on newborn screening in most states. With appropriate hormone replacement therapy, children with CAH grow up healthy and active. The key is consistent medication, stress dosing during illness, and regular follow-up with a pediatric endocrinologist.

Growth Hormone Deficiency Signs

Growth hormone deficiency (GHD) occurs when the pituitary gland does not produce enough growth hormone to support normal growth. It affects approximately 1 in 4,000-10,000 children. In babies, it may present with low blood sugar (hypoglycemia), prolonged jaundice, small genitalia in boys, or slow linear growth. In older infants and toddlers, the hallmark sign is a progressively declining growth velocity, causing the child to fall farther behind peers on the growth chart. GHD is treatable with daily growth hormone injections, and early treatment leads to better outcomes.

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