Newborn Low Blood Sugar: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Newborn Low Blood Sugar?
A pediatrician, a doctor who treats babies and children, usually manages newborn low blood sugar. A neonatologist, a doctor who cares for newborns, may treat babies who need hospital care. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is newborn low blood sugar?
Newborn low blood sugar is also called neonatal hypoglycemia. It means low blood sugar, also called glucose, in the first few days after birth. Babies need glucose for energy. Most of that glucose is used by the brain. Neonatal hypoglycemia is common.
Symptoms
Babies with low blood sugar may not have symptoms. If a baby has a risk factor, nurses in the hospital will check the blood sugar level, even if there are no symptoms. Doctors usually check the blood sugar of babies with these symptoms:
- Bluish-colored or pale skin.
- Pauses in breathing, called apnea.
- Irritability or listlessness (very low energy).
- Loose or floppy muscles.
- Poor feeding or vomiting.
- Problems keeping the body warm.
- Tremors, shakiness, sweating, or seizures.
A seizure, or trouble or abnormal breathing, is an emergency. See the section on when to see a doctor.
Causes and who gets it
The glucose level can drop if there is too much insulin in the blood. Insulin is a hormone that moves glucose from the blood into tissues. It can also drop if the baby cannot make enough glucose, is using more glucose than is made, or cannot take in enough by feeding.
Low blood sugar is more likely in babies with one or more of these risk factors:
- Born early, has a serious infection, or needed oxygen right after delivery.
- Mother has diabetes.
- Slower than expected growth in the womb during pregnancy.
- Smaller or larger in size than expected for their gestational age (how many weeks of pregnancy).
If you have diabetes during pregnancy, work with your provider to control your blood sugar level. Be sure that your newborn's blood sugar level is monitored after birth.
How doctors diagnose it
Newborns at risk should have blood tests often after birth, using a heel stick. Tests continue until the baby's glucose level stays normal for about 12 to 24 hours. Other tests may include newborn screening for metabolic disorders, such as blood and urine tests.
Treatment
Babies with low blood sugar need extra feedings with mother's milk or formula. A baby who breastfeeds may need extra formula if the mother cannot make enough milk. Hand expression and massage can help mothers express more milk. A sugar gel may be given by mouth for a short time if there is not enough milk. Sugar gel given by mouth is increasingly recommended as a first treatment.
A sugar solution may be given through a vein (IV) if the baby cannot eat by mouth, if blood sugar does not improve with feeding, or if it is very low. In rare cases, the baby may also get medicine to raise blood sugar. Treatment continues until the baby can keep blood sugar steady, which may take hours or days. Babies who were born early or small, whose mothers had diabetes, or who have other problems may need treatment for longer.
The outlook is good for newborns who do not have symptoms, or who respond well to treatment. Low blood sugar can return in a small number of babies after treatment, so levels are checked after treatment has stopped. Very severe or long-lasting low blood sugar can cause long-term problems with brain development.
When to see a doctor
Call 911 or go to the emergency room if your baby has a seizure, trouble or abnormal breathing, pauses in breathing, bluish or grey skin, or is limp or very hard to wake. Blood sugar is usually checked for babies with the symptoms listed above.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can follow your baby after a hospital stay, since blood sugar levels are checked again after treatment stops.
Common questions
Is newborn low blood sugar dangerous?
It can be, but the outlook is good for newborns who do not have symptoms or who respond well to treatment. Very severe or long-lasting low blood sugar can cause long-term problems with brain development.
Which babies are more likely to have low blood sugar?
Babies who are born early, whose mothers have diabetes, or who are smaller or larger than expected are more likely to have it. Nurses check the blood sugar of babies with a risk factor, even if there are no symptoms.
How is newborn low blood sugar treated?
Newborn low blood sugar is treated first with extra feedings of mother's milk or formula. A sugar solution through a vein may be needed if the baby cannot eat by mouth or the blood sugar level is very low.
Can newborn low blood sugar come back after treatment?
Yes, low blood sugar can return in a small number of babies after treatment. It is more likely to return when babies are taken off IV fluids before they are fully ready to eat by mouth.
Does low blood sugar always cause symptoms in a newborn?
No, some babies with low blood sugar have no symptoms.
Sources
- MedlinePlus - Low blood sugar - newborns
- National Library of Medicine (PubMed Central) - Clinical Aspects of Neonatal Hypoglycemia: A Mini Review
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
