Hypoglycemic Reaction (Newborn) 

Blood sugar is also called glucose. The body uses this 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. This causes a hypoglycemic reaction.

Signs of a hypoglycemic reaction in newborns include:

  • Being irritable, jittery, or shaking (tremors)

  • A high-pitched cry

  • Feeding problems

  • Lack of energy (lethargy) or limpness

  • Skin has a blue color

  • Seizures

  • Very fast breathing or heart rate

  • Low body temperature, and trouble staying at their body temperature

Hypoglycemia can also be a sign of infection. So your baby may have tests to make sure an infection is not present. Hypoglycemia occurs most often in babies born too early (prematurely) or with low birth weights. 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 young baby. Follow the provider’s instructions for feeding.

General care

  • Be aware of your baby’s signs of hunger and low blood sugar.

  • Allow time for frequent, quiet feedings. If your baby is not feeding well, talk with your healthcare team about methods that will help.

  • 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 him or her 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.

  • If you have diabetes and are breastfeeding, watch your glucose levels closely.

  • If instructed to do so, check your baby’s blood sugar as directed.

If symptoms return

Feed your baby breastmilk or infant formula, and 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:

  • Fever higher than 100.4°F (38°C) rectal, or a temperature lower than normal

  • Low blood sugar symptoms come back (see symptoms above)

© 2000-2022 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.

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