Low blood sugar that was not caught

What is it?

Before birth, glucose crosses the placenta continuously. At delivery that supply stops. The baby has to switch to using stored fuel and making their own glucose.

Almost every newborn's blood sugar dips in the first hours during that switch, and then recovers. That dip is normal. ³

Some babies cannot make the switch.

• A baby whose mother had diabetes has been producing extra insulin. The sugar supply stops at birth and the insulin does not. ⁴
• A baby who is small or growth restricted has few stores to draw on.
• A baby born late preterm has an immature system for making glucose.
• A baby who is cold, infected or stressed burns through what they have faster. ⁵

If the level stays low, brain cells run out of fuel. The occipital lobes at the back of the brain are characteristically affected, which is why cortical visual impairment is the common lasting consequence. ^{2 6}

Why the threshold question is genuinely unsettled

There is real professional disagreement about the exact number that should trigger treatment, and different guidance uses different values depending on the baby's age in hours and whether they have symptoms. ^{3 1}

This site does not publish a threshold number, because quoting one without its full context would be misleading. What both approaches agree on is that a persistently low level needs treatment, and a level that will not come up needs investigation.

What does standard care look like?

Risk-based screening. Guidance names the groups to screen: large or small for gestational age, infants of mothers with diabetes, late preterm babies, and symptomatic babies. ³

A defined screening schedule, with checks before feeds and at set intervals through the first hours and days. ³

Confirmation of low bedside readings on a laboratory sample. ³

Treatment and recheck. Feeding, oral dextrose gel, or intravenous glucose depending on the level and the baby, followed by a recheck. ³

Escalation where feeding alone does not correct the level.

Investigation of persistent low glucose, with a critical sample drawn while the glucose is low, because the results are only interpretable at that moment. ¹

Attention to temperature and to feeding, both of which affect glucose.

Assessment for brain injury where hypoglycemia was severe or prolonged, including MRI and vision assessment. ^{2 6}

What can go wrong?

A baby with a named risk factor never screened, or not screened on the recommended schedule. ³

Screening based on symptoms, in a condition where most affected babies have none. ³

A low bedside reading not confirmed on a laboratory sample, where meters are least accurate. ³

A low value treated once and not rechecked.

Intravenous glucose not started when feeding alone was not working. ³

Persistent low glucose not investigated, so an underlying cause such as excess insulin production was not found. ¹

Symptoms attributed to normal newborn behavior, such as jitteriness, sleepiness or poor feeding.

Seizures not recognized as a possible sign of low blood sugar. ⁷

Maternal diabetes not identified in pregnancy, where screening guidance exists. ⁴

Whether any of this amounts to a departure from the standard takes a physician expert reading the whole record.

Which injuries can follow?

• Low blood sugar and brain injury. ²
• Cortical visual impairment, the characteristic consequence, which a standard eye examination will not detect. ⁶
• Neonatal seizures. ⁷
• Epilepsy after birth injury. ⁸
• Cerebral palsy where injury is significant. ⁹
• Developmental delay and later learning differences, particularly visual and spatial. ¹⁰

What does this look like in the records?

Request every glucose value with the exact time it was taken. That is the core record on this page. ¹¹

Also request

• Which risk factors were documented, and what screening schedule that put the baby on. ³
• Whether low bedside readings were confirmed in the laboratory.
• What treatment was given after each low reading, and what the recheck showed.
• Feeding records and weights.
• Temperature readings.
• Any critical sample drawn while the glucose was low, and its results. ¹
• The maternal record, including diabetes screening results. ⁴

Then

• Any MRI report, and specifically whether the occipital lobes are involved. ²
• Any EEG report. ⁷
• Vision assessments, and whether cortical visual impairment was considered. ⁶

What to work out from the values

How low the glucose went, how long it stayed low before it came up, and whether it came back down afterward.

What can you do this week?

1. Request the complete labor and delivery record for you and your baby. The records request builder writes the letters for you.
2. Write down what you remember while it is fresh, using the delivery timeline builder.
3. Read how to read your labor and delivery records before the records arrive.
4. Check the deadline to file in your state with the statute of limitations lookup.