Newborn Blood Glucose

Blood glucose is the sugar that travels in your bloodstream. It also provides energy to all of your cells. For your newborn the blood glucose is an important source of energy for them. It will help with healthy growth and development. When your baby is first born their main source of glucose was from the placenta and umbilical cord. These two sources allow your baby to have a storage of energy for birth and the first few days of life before the mother’s breast milk has come in. Once the mother’s breast milk comes in, which is about day 3 after delivery, then that becomes the primary source. Formula fed babies or breastfed babies will get sugar from the formula or breastmilk and will change the sugar to glucose in the body.

Neonatal Hypoglycemia & Neonatal Hyperglycemia

Newborn babies can have neonatal hypoglycemia which is lower than normal glucose at birth. It is less common but a newborn can also have neonatal hyperglycemia which is higher than normal glucose at birth.

Neonatal hypoglycemia is more common in newborns and requires some extra testing to be done on your baby to make sure their levels normalize. Symptoms can be vague for neonatal hypoglycemia. Symptoms can include a weak high pitched cry, tremors, sweating, feeding difficulties, irritability, or seizures. Your baby’s levels are low if they measure 30 mg/dL or less within 24 hours of being born. Or 45 mg/dL or less in the first few days.

There can be a lot of different causes for neonatal hypoglycemia. The most commonly seen reasons for your baby to have low glucose levels are if they are later-preterm babies that are born between 34-36 weeks. Being large for their gestational age. Being small for their gestational age. Infants that have a mother who had diabetes before or during the pregnancy. Other causes can be that there wasn’t enough glucose supply at birth, depleted fat stores, increased glucose use, increased metabolism, there was too much insulin production in utero, or the pituitary or adrenal glands are failing.

Low glucose levels can last only a few hours. Sometimes they can last between 24-72 hours. It is rare for low levels to last a long time, but can still happen. If your baby’s levels are still low after 24 hours your doctor may suggest running more tests to see what could be causing the continuation of low levels.

Newborn Blood Glucose Testing

Not all babies need to undergo a glucose test. A glucose test is done with a heel prick to obtain a small amount of blood. The tiny amount of blood is put on a strip attached to a glucometer to measure the levels. The first heel prick will be between 3-4 hours after birth usually after the second feed. After that all other heel prick tests will be repeated before you feed your baby. Levels should be anything above 45 mg/dL to not be considered low. You should receive the result immediately from the glucometer. For babies that are 36-37 weeks or there was diabetes present in the mother before or during pregnancy then at least 4 heel sticks will be necessary to check the baby’s levels. In other cases your baby may need a heel stick before every feed for the first 12 hours of their lives.

The babies that will warrant a glucose check are babies that are preterm, born before 36 weeks. If the baby is small for their gestational age. If the baby is large for their gestational age. If the mother has diabetes before or during pregnancy. If the baby has a rare medical condition. If the mother has received labetalol within two weeks of delivery. If the mother has received antenatal steroids within two weeks of delivery.

If at any time your baby’s levels are not higher than then 45 mg/dL the nurses and pediatricians at the hospital will talk to you about ways to help the baby get their levels up higher. One way is a glucose gel that goes inside the baby’s cheek and dissolves. If you are breastfeeding, using formula for supplementation can also help raise glucose levels. Expressing breast milk and feeding the baby with a bottle can also help make sure the baby is drinking enough. If none of these are working and blood glucose is still low your baby may need IV treatment.

Takeaway

Early and frequent breastfeeds can help prevent low blood sugar from occurring in your newborn baby. Not all babies will need blood glucose checks when they are first born. Only if they fit one of the more common reasons for low blood glucose to be present. Levels usually stabilize in most newborns between 12 and 72 hours after being born. It is rare for them to remain low. If they do remain low, without treatment your baby may have development or growth delays or problems.