Hypoglycemia in the Newborn

Hypoglycemia in the Newborn

Neonatal hypoglycemia is one of the most common metabolic conditions in newborns, particularly during the first 4 to 5 days post-birth.⁴ This period is the highest risk for developing hypoglycemia due to physiological changes and reliance on caregivers for feeding. If feeding cues are missed, or if a sleepy baby is not awakened to feed, metabolic needs can go unmet, further delaying milk supply transition. Although mild hypoglycemia’s impacts are less understood, significant clinical concerns arise from persistent hypoglycemia, which can adversely affect brain development.^5,6

During pregnancy, glucose is supplied continuously through the placenta to enable growth and development of the baby. During physiological labour, glucose levels rise to an average of 4.6 mmol/L from an average of 3.5mmol/L in later pregnancy.^7,8 For babies who are born by planned caesarean birth, the average glucose level after birth is slightly lower at 3.9 mmol/L and instrumental birth such as ventouse birth, the average glucose is around 5.8 mmol/L on average.^9,10 Following the clamping and cutting of the cord, the baby’s liver begins taking over in glucose control. Within the first 30 minutes there is a fall in glucose levels where the neonate is using energy to transition to extrauterine life without the placenta. On average this fall is to around 2.9mmol/L, but this increases to an average of 3.1mmol/L by around 60-90 minutes.^9,10,11 Feeding early in this first hour helps to maintain normal glucose levels at this stage. In healthy breastfed babies, most will remain at around an average of 3.3 mmol/L but by 4 days of life, this will have increased to an average of 4.5 mmol/L. ^8,9,10

For healthy term infants, the lower threshold for glucose levels is below 2.6 mmol/L, but treatment thresholds vary regionally. A randomised controlled trial indicated no differences in neurodevelopmental outcomes at 18 months old between treatment thresholds of 2.0 mmol/L and 2.6 mmol/L. Many hospitals in the UK have reduced the treatment and intervention thresholds to 2.0 mmol/L and below, or alternatively 2.6 mmol/L and below if there are symptoms of hypoglycemia in the newborn.

In severe hypoglycemia, hypoxic ischaemic encephalopathy (brain injury) and neonatal death can occur. A review of NHS litigation authority claims from 30 newborns born over 36 weeks gestation between 2002-2011 highlighted a need for education for healthcare professionals to assess, diagnose and treat neonatal hypoglycemia.¹⁵ 25 of these 30 claims where babies were harmed cost a total of £162,166,677 in litigation claims.

Risk Factors

Infants born to diabetic mothers are at greater risk due to hyperinsulinemia.^{5,6,14,17,18,19} Other risk factors include:

 • Low birth weight (under the 2nd centile) 

• Preterm birth 

• Intrauterine growth restriction (IUGR) 

• Sepsis

• Use of alpha-beta blockers 

• Low cord gases at birth 

• Hormonal deficiencies 

• Metabolic conditions

• Poor infant feeding⁵

Symptoms of Hypoglycemia

Symptoms of hypoglycemia in newborns can be subtle and nonspecific, complicating early detection. Common signs include:

 • Jitteriness

 • Poor feeding (not waking for feeds, infrequent feeding, poor latch) 

• Lethargy 

• Temperature instability 

• In severe cases, seizures or altered consciousness.^4,5,17,18

Prevention

Prevention begins during pregnancy, where educating women about blood sugar control can reduce complications. For mothers with risk factors, antenatal hand expressing can provide a milk supply for early feeds, enhancing parental confidence. Identifying at-risk infants at birth and implementing management strategies are crucial.^20,21 Post-birth, keeping babies warm, facilitating skin-to-skin contact, and feeding within the first hour are essential.^22,23

Healthcare providers should closely monitor at-risk infants since early intervention prevents complications. If a baby appears sleepy, parents should be educated to wake them to feed. Regular feeds every three hours are recommended during blood glucose monitoring. Parents should also receive guidance on recognising feeding cues and the importance of timely feeding to avoid hypoglycemia.

Treatment for Hypoglycaemia

The primary treatment for hypoglycemia is prompt glucose administration. For mild to moderate cases, oral feeding with breast milk or infant formula can restore blood glucose levels.¹⁸ If levels remain low after feeding, an oral glucose solution should be administered. Severe cases may require intravenous dextrose.^4,5 Hospital guidelines may vary, but continuous research and education remain vital for improving outcomes.

Educating Parents on Feeding Cues

Recognising feeding cues is crucial for parents to meet their infant's needs. Cues may include hand-to-mouth movements, sucking fingers, and rooting behaviours. Hypoglycemia in newborns is a preventable condition, and healthcare professionals play a vital role in its assessment, detection, and treatment, often in collaboration with parents. 

 Healthcare providers can support parents by:

 • Observing feeding patterns and raising awareness

 • Promoting responsive feeding practices

 • Encouraging a calm feeding environment for both infant and caregiver

 • Providing lactation support and addressing any breastfeeding concerns

 • Encouraging colostrum harvesting for all parents, but particularly mothers with risk factors

This scientific article has been authored by an expert who received compensation from MAM. 

 Published in June 2025.