Hypoglycemic Reaction (Newborn)
Blood sugar is also called glucose. The body uses glucose as energy. Before birth, babies rely on their mothers for glucose. They don’t make their own. After birth, the umbilical cord is cut. The young baby then depends on feedings for glucose. If the first feeding is delayed longer than 3 to 6 hours, the newborn may develop low blood sugar (hypoglycemia). This is a common problem in the first few days of life. It causes a hypoglycemic reaction.
Signs of a hypoglycemic reaction in newborns include:
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Being irritable, jittery, or shaking (tremors)
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A high-pitched cry
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Feeding problems
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Lack of energy (lethargy) or limpness
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Skin that is blue in color
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Seizures
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Very fast breathing or heart rate
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Low body temperature, and trouble staying at their body temperature
Hypoglycemia can also be a sign of infection. Your baby may have tests to make sure they don't have an infection. Hypoglycemia occurs most often in babies born too early (prematurely) or at a low birth weight. It may also occur in babies born to mothers who have diabetes.
Hypoglycemia is diagnosed in newborns by testing blood. Low blood sugar must be carefully watched to prevent a serious problem. Babies who are premature or too ill to feed will be given nutrition by a tube to the stomach or into a vein. If hypoglycemia lasts, the healthcare provider will test for other causes.
Home care
Your child’s healthcare provider may prescribe a special feeding schedule for your baby. Follow the provider’s instructions for feeding.
General care
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Know your baby’s signs of hunger and low blood sugar.
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Allow time for frequent, quiet feedings. If your baby is not feeding well, talk with your healthcare team about ways that will help.
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Keep your baby dressed warmly. Newborns have trouble controlling their body temperature. They can get cold easily. Cold may trigger a hypoglycemic reaction. If your baby has a lower body temperature than normal, warm them as soon as possible. Add more layers and a cap to hold in body heat. Remove any damp clothes and replace with warm, dry clothes. Keep your baby away from cold drafts.
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If you have diabetes and are breastfeeding, watch your glucose levels closely.
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If told to do so, check your baby’s blood sugar as directed.
If symptoms return
Feed your baby breastmilk or infant formula. Then call your baby's healthcare provider.
Follow-up care
Follow up with your baby’s healthcare provider, or as advised. If lab tests were done, you will be told of any results that may affect your baby’s care.
When to get medical advice
Call your baby’s healthcare provider right away if any of these occur:
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Fever higher than 100.4°F (38°C) rectal, or a temperature lower than normal
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Low blood sugar symptoms come back (see symptoms above)
Online Medical Reviewer:
Callie Tayrien RN MSN
Online Medical Reviewer:
Liora C Adler MD
Online Medical Reviewer:
Raymond Kent Turley BSN MSN RN
Date Last Reviewed:
12/1/2022
© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.