Neonatal Hypoglycemia

Neonatal Hypoglycemia has received an upsurge in attention recently. As breastfeeding is pulled more and more in to the spot light, hospital interventions are being painted in a much more negative light. One such hospital intervention is the routine testing of infant blood sugar, which is used to justify formula supplementation of newborns.

Neonatal Physiology and Hypoglycemia

Glucose is the main source of energy for humans, and up to 90% of our total glucose is consumed by the brain. While in the womb, the neonate is attached to the umbilical cord, which supplies a constant infusion of glucose to the developing brain. Once born, that supply is cut off, and the infant's body must then change over to an enteral supply of glucose. During the 3rd trimester, the infant begins laying down liver glycogen stores. These glycogen stores will act as fuel until the mother's breast milk volume increases and breastfeeding is established. [1]

Within the first few hours of a newborn's life, it's is physiologically normal for there to be a drop in blood sugar. When you move from a constant supply to intermittent supply of glucose, there is going to be some fluctuation. Ideally, the infant begins metabolizing stored glycogen and that, combined with regular breastfeeding of colostrum and skin to skin contact with the mother, allows the infant to maintain his blood glucose levels on his own. The blood sugar levels will then begin to rise, normalizing around the 24 hour mark. [1],[2],[3]

When Hypoglycemia Becomes An Issue

Some infants are unable to maintain their blood sugar. Preterm infants are at a particularly high risk, since they oftentimes lack the liver glycogen stores that full-term, healthy newborns have. In some instances, delaying the first breastfeeding can also result in blood sugar levels that are too low. While there is no single cut-off point for determining when an infant is hypoglycemic, there are different levels of intervention that are implemented at different points in the first days of life, all of which have the ultimate goal of preventing full-blown hypoglycemia. [3]

During full-blown hypoglycemia, the brain experiences a decrease in the amount of glucose it has available for fuel. Without that fuel, neurological damage can result. Treating Neonatal Hypoglycemia in a timely manner is of utmost importance and involves maintaining blood sugar levels while they are within treatment thresholds, BEFORE they reach the level of neurological impairment. Since no one really knows at what level an infant is going to experience neurological impairment as a result of low blood sugar, the therapeutic threshold of <40 mg/dL has been established as the point at which therapy becomes necessary. That level is variable though, and depending on who is responsible for care of an infant, therapy may begin at a higher blood sugar level for sick or preterm infants, or may be allowed to go lower in infants who are otherwise asymptomatic. [4]

The American Academy of Pediatrics established guidelines in 2011 for the monitoring and treatment of Neonatal Hypoglycemia, with 45 mg/dL designated as the target glucose level. The AAP also recommends against the routine testing of blood glucose in full term, healthy newborns. Rather, the implementation of a glucose screening program should target those infants who are at risk. [12] The rationale for such a recommendation is that routine blood sugar testing usually results in aggressive supplementation of infants who would have otherwise been breastfed. Breastfed infants have higher levels of ketone bodies, which may provide protection against hypoglycemia-induced neurological impairment, since the brain is also able to use ketones for fuel. [5],[7]

Stage 1 Intervention

The first stage of intervention applies to all infants, regardless of blood sugar levels. FEED THE BABY. Breastfeeding should be initiated within the first 60 minutes of an infant's life. If the infant is separated from the mother, or the mother is unable to bring the baby to breast, or the baby will not latch, then she should begin to hand express by the end of that first hour. The expressed milk can then be given to the infant through an alternative device (syringe, cup, dropper, SNS, etc). Colostrum is the preferred food source for preventing hypoglycemia because it is high in amino acid precursors and fatty acids which prompt the newborn's body to undergo gluconeogenesis, while minimizing insulin secretion. [5]

Stage 2 Intervention

The second stage of intervention is once again to feed the baby. If an infant is presenting with blood sugar levels below 40 mg/dL, but it asymptomatic, then protocol is to simply continue to offer breastfeeds. In addition to offering breastfeeding, it may be necessary to offer a small supplement of expressed colostrum with a syringe. If expressed colostrum is not available, human donor milk or formula can be used. Blood glucose can then be re-measured 30-60 minutes later. [4],[6],[7]

Stage 3 Intervention

Stage 3 intervention is for infants who are asymptomatic with a sugar level < 25 mg/dL, infants who are symptomatic with a sugar level < 40 mg/dL, or infants who have a persistent hypoglycemia who do not improve by increased breast milk feeding. It is also for infants who are unable to tolerate oral feeds.

The third stage of intervention involves the administration of an IV bolus of dextrose, followed by an intravenous infusion. Once an intravenous infusion of dextrose has been started, it cannot be stopped without first titrating down the dose. Sudden cessation of IV dextrose can result in reactive hypoglycemia. Infants who are unable to maintain their blood sugars are usually referred to the Neonatal Intensive Care Unit. [4],[6],[7]

Use of Infant Formula in the Treatment of Neonatal Hypoglycemia

With an increased awareness of the hazards of not breastfeeding, supplementing infants with formula is almost always regarded with disdain, regardless of the reason for the supplementation. When it comes to treating Neonatal Hypoglycemia, the first choice of supplement is always going to be breast milk, first from the mother, then from another mother.

But in some instances, breast milk is not available. The mother may be recovering from a difficult delivery, the infant may be in the NICU for other reasons, the mother may not have any success hand expressing or using a pump, or donor milk may not be available at that hospital. In those instances, formula is the next option.

There are some breastfeeding supporters who advocate for the use of IV dextrose as a "non-formula" alternative to supplementation, but I feel that kind of management goes against not only evidence but also better judgement.

Treating Neonatal Hypoglycemia should always involve the stage of intervention that is the least aggressive, but is going to allow for the best possible neonatal outcome, as well as the greatest preservation of breastfeeding. In infants who are not symptomatic and who can tolerate oral feedings, supplementation with a clinically indicated amount of formula is preferable to an IV infusion of dextrose. [6] IV dextrose is a much larger intervention, oftentimes involving moving the infant to the NICU. Such maternal/infant separation does more to undermine breastfeeding than a one-time limited formula supplementation. Infants who are allowed to be orally supplemented with expressed milk or formula can remain skin-to-skin with the mother. This type of kangaroo care helps the infant to regulate his body temperature, which results in less caloric expenditure and thus greater glycemic management. Oral supplements can be given in a way that does not affect breastfeeding, such as using an at-breast supplementation device or a syringe. And the duration of hospital stay is shorter than an infant receiving an IV infusion.

The other downside to IV infusions of dextrose is aluminum content. Many IV medications, including dextrose, contain aluminum. [8],[9] Intravenous infusions of aluminum are associated with larger accumulations of aluminum in the body, and neurological delays. This is of particular concern with preterm infants, and studies on preterm infants who receive Total Paraenteral Nutrition have shown slight neurological delays as a result of the aluminum given in the infusions. [10],[11] Formula also contains aluminum, but orally obtained aluminum is much easier eliminated from the body and very little is absorbed and accumulated.

For that reason, lower-level interventions should always be preferred and used to prevent Neonatal Hypoglycemia from getting to the point where an IV infusion of dextrose is indicated. IV dextrose should not be used as an "alternative" to giving an infant formula. Proper management of breastfeeding with neonatal hypoglycemia should, in almost all cases, remove the need for formula in the first place, and there is no evidence to back of the "routine" supplementation of infants with formula. [2]

References:

1. American Academy of Pediatrics. 1999. "Neonatal Hypoglycemia"
http://pedsinreview.aappublications.org/content/20/7/e6.full

2. International Breastfeeding Center (Dr. Jack Newman). 2009. "Hypoglycaemia of the Newborn (Low Blood Sugar)"
http://www.nbci.ca/index.php?option=com_content&id=71:hypoglycaemia-of-the-newborn-low-blood-sugar&Itemid=17

3. World Health Organization. 1997. "Hypoglycaemia of the Newborn: Review of the Literature"
https://apps.who.int/chd/publications/imci/bf/hypoglyc/hypoclyc.htm

4. National Neonatology Forum. 2000-2013 "Management of Neonatal Hypoglycemia"
http://nnfpublication.org/Uploads/Articles/4c86270b-ac2d-4c04-b55b-abc5add3e623.pdf

5. Walker, Marsha. 2009. Breastfeeding Management for the Clinician: Using the Evidence

6. Academy of Breastfeeding Medicine. 2006. "ABM Clinical Protocol #1: Guidelines for Glucose Monitoring and Treatment of Hypoglycemia in Breastfed Neonates"
http://www.bfmed.org/Media/Files/Protocols/hypoglycemia.pdf

7. International Lactation Consultant Association. Marinelli, Kathleen. 2012. "Hypoglycemia and the Breastfeeding Newborn"
http://www.ilca.org/files/USLCA/Education_Resources/Webinar_Materials/11-8-12/Hypoglycemia%20Marinelli%20USLCA%202012.pdf

8. B. Braun Medical, Inc. 2008. "Dextrose Injection USP"
http://dailymed.nlm.nih.gov/dailymed/archives/fdaDrugInfo.cfm?archiveid=8218

9. Journal of Parenteral and Enteral Nutrition. 2010. "Aluminum content in intravenous solutions for administration to neonates: role of product preparation and administration methods."http://www.ncbi.nlm.nih.gov/pubmed/20467015

10. American Academy of Pediatrics. 2009. "Aluminum Exposure From Parenteral Nutrition in Preterm Infants: Bone Health at 15-Year Follow-up"http://pediatrics.aappublications.org/content/124/5/1372

11. Proceedings of the Nutrition Society. 2011. "Aluminium exposure from parenteral nutrition in preterm infants and later health outcomes during childhood and adolescence."http://www.ncbi.nlm.nih.gov/pubmed/21781356

12. American Academy of Pediatrics. 2011. "Postnatal Glucose Homeostasis in Late-Preterm and Term Infants"http://pediatrics.aappublications.org/content/127/3/575.full