Hypoglycemia in the Neonate

Learning Objectives:

  • Identify risk factors for hypoglycemia in the newborn
  • Identify signs & symptoms of hypoglycemia
  • Learn how to test for hypoglycemia
  • Learn how to interpret results of test
  • Learn how to respond

What is hypoglycemia?

hy·po·gly·ce·mi·a

[hahy-poh-glahy-see-mee-uh]

NOUN [PATHOLOGY.]

  1. an abnormally low level of glucose in the blood.

(True or False)

All babies experience a postnatal fall in glucose levels after birth? TRUE

  • This is the most common metabolic abnormality – consequence of insufficient stores of glycogen or overuse of these stores (*see risk factors)
  • Normal for blood glucose to fall for small period of time 1-2 hours after birth, typically stabilized around 3-4 hours
  • In first 72 hours of life there is a sharp drop in glycogen stores in the liver (the healthy newborn can compensate for this)
  • Prior to birth, fetus is exposed to nearly constant blood glucose levels, about 60-70% of maternal levels
  • The moment the cord is clamped, the newborn has to find a way to maintain balance of glucose, which is essential for neonatal brain function.

What are the risks? Brain damage or death (early detection is necessary)

Who is at risk?

  • Low Birth Weight Babies (decreased hepatic glycogen stores and reduced subcutaneous fat stores for quick utilization)
  • Small for dates
  • Preterm babies
  • Those born to (gestational) diabetic mothers
  • Increased risk especially in the first 6 hours of life. (supply of glucose from the mother is removed while insulin production is still elevated)
  • Neonatal hypoglycemia can also occur when mother is placed on a very restrictive diet (fetus is under-supplied with glucose)
  • LGA – if birth weight is > 4000 g, the baby is at increased risk of developing hypoglycemia within 4 hours
  • Postmature
  • Sick term infants
  • Septic
  • Hypoxic Infants (carbohydrate metabolism is upset by lack of oxygen, excessive metabolism of glycogen occurs)
  • Baby born after stressful labor
  • Not allowing full placental transfusion
  • Those who do not nurse soon after birth
  • Hypothermia (glucose is consumed to produce energy for heat production)

What are the signs and symptoms?

Jitteriness, cyanosis, lethargy, seizures/convulsions, apnea, hypotonia, poor feeding/reluctant to feed, irritability in handling, irregular respirations, hypothermia

Are there always signs/symptoms

Many are asymptomatic at first

The aim is to commence treatment prior to signs appearing!

How do you test?

Device used

About glucometer

  • Device that uses plasma to derive the reading
  • One that uses an electric current vs color change (improved accuracy)
  • Whether it’s appropriate for testing newborns

Collection technique

  • Check capillary glucose (heel prick) (Chart V p967)
  • Avoid venous stasis

~ exacerbated in infant who is cold or has experienced recent hypoxia

  • Maximize blood flow by warming the heel
  • Confirm suspicious values with venous samples (Would you? Refer?)

SFMP states the mixture of blood and alcohol may cause a high glucose reading and should be avoided

Suck Test for tremor evalulation

  • Cessation of tremors (both hands) when baby sucks on a finger
  • If tremors don’t cease, baby may likely be truly hypoglycemic or hypocalcemic (low serum calcium)

What are the ranges?

There is no strict definition of cutoff value when intervention is necessary.

Any symptomatic newborn should be treated regardless of their exact glucose level

Normal

50-60 mg/dL

Average level of 60-70 mg/dL (3.9 mmol/l) 4-72 hours post birth

Borderline

Borderline glucose level 40-45 mg/dL

Need intervention

*If symptomatic, intervene with plasma glucose of 45 mg/dL

*If asymptomatic, intervene at 35 mg/dL

<47 mg/dl (2.6 mmol/l) found to acutely effect regions of brain with high glucose demand: considered lower limit of normal

Blood sugar levels < 1.5 mmol/l in full-term infants, a level of 2.2 mmol/l after 72 hours (27 – 39.6 mg/dL)?!?!?! – lowest seen

>125 mg/dl (in term babies) hyperglycemia in newborn

How do you respond?

Timeframe

Test baby (those at risk/those with symptoms) before the second feeding

Feed baby (breast/formula)

Recheck glucose 1 hour later

Repeat test in 30 min (Varney’s)/1 hour (UDT) unless improvement is obvious

It may take a few dropper feedings to correct hypoglycemia

Prevention

  • Nursing is the best way to ensure normal glucose levels are maintained
  • Nurse in the 1st hour of life (ideal), within 3 hours of birth is sufficient

(this will help during the adjustment of normalizing insulin production and lower blood sugar as it will allow the baby to begin to store glycogen again)

  • Frequent feeding ≤ 3 hours
  • Those who remain hypoglycemic despite nursing may have a more rare pancreatic disorder
  • Hypoglycemia may be secondary to underlying condition, such as galactosemia, defect in their glucose regulating mechanism or sepsis
  • Monitor/Eliminated causes of stress
  • Temperature control (keep warm)
  • Breathing problems

Review:

1)Knowing what you do now, what will that change?

2)How often do you send baby home (or leave) prior to:

  • Establishing breastfeeding?
  • Ensuring a full feeding?

3)Will you carry a glucometer/supplies for collection?

  • To the birth
  • To post partum home visits

Should you?

4)How long do you tell parents it’s okay for baby not to feed in the first 24 hours?

  • Sometimes we discuss the recovery period and tell them baby may not be interested in feeding for up to ___ hours
  • Sometimes they skip a feeding…how long is too long?

References:

Holistic Midwifery Volume II p 562-563, 598-599, 1343-1344

Varney’s p 966

Understanding Diagnostic Tests p 1139-1141, p 432 & 440

Myles Textbook for Midwives 12 ed. p 362, 573, 576, 619

Myles Textbook for Midwives 15th ed. p 930

Skills for Midwifery Practices 2nd ed. p 328-331

Heart & Hands 4th ed. p 198, 201