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Key messages

  • Poor glycaemic control during embryogenesis can result in a four- to eight-fold increase in congenital malformations.
  • Maternal hyperglycaemia can contribute to macrosomia.
  • The infant of a mother who has uncontrolled diabetes may have perinatal and neonatal complications.

Poor maternal glycaemic control during embryogenesis can result in a four- to eight-fold increase in congenital malformations including:

  • cardiac defects
  • CNS defects (including anencephaly and spina bifida)
  • genitourinary and limb defects.

However, these are not seen with an increased frequency in infants of diabetic fathers, or mothers where gestational diabetes develops after the first trimester.

Perinatal complications of diabetes in pregnancy

Perinatal complications include Increased perinatal mortality due to:

Birth injury may be caused by:

  • shoulder dystocia
  • brachial plexus trauma
  • over-representation of IUGR (even if mother does not have pre-existing IDDM with small vessel disease) - seen in 20 per cent of IDMs.

Neonatal complications of diabetes in pregnancy

Neonatal complications include:

  • polycythaemia and hyperviscosity due to:
    • increased erythropoiesis secondary to fetal arterial hypoxaemia secondary to hyperinsulinism
    • shift in blood from placenta to fetus during hypoxia
  • hypoglycaemia
    • incidence varies from 25-40 per cent
      • defined as BSL < 2.6 mmol
      • note: many infants who are hypoglycaemic may be asymptomatic
  • hypocalcaemia (due to functional hypoparathyroidism and hypomagnesaemia). Occurs in approximately 50 per cent of insulin-dependent diabetics. Suspect hypocalcaemia if there is:
    • irritability
    • coarse tremours
    • jitters
    • tongue thrusting
    • twitches
    • apnoea
    • seizures
  • hypomagnesaemia
    • (due to maternal hypomagnesaemia/increased renal losses with glycosuria)
  • hyperbilirubinaemia due to:
    • polycythaemia (increased RBC mass)
    • increased extravascular haemolysis (bruising, cephalhaematoma)
    • delayed oral feeding (increased enterohepatic circulation)
    • liver immaturity
  • hypertrophic and congestive cardiomyopathy are:
    • usually asymptomatic
    • usually resolve by eight to 12 weeks
  • respiratory distress due to:
    • delayed fetal lung maturation (insulin impedes glucocorticoid effect)
    • prematurity
    • increased incidence of Caesarean section in near-term deliveries/complicating 'wet lung syndrome'.

Neonatal management

Babies whose birthweights are between the 10th and 90th percentiles and therefore appropriate for gestational age (not growth-restricted or macrosomic) and/or infants of diabetic mothers not on insulin are at low risk for hypoglycaemia and can be safely screened on the postnatal ward to keep mother and baby together.

Management of hypoglycaemia involves:

  • BGL monitoring (refer hypoglycaemia). Blood glucose monitoring is required for:
    • infants of a woman who has diabetes requiring insulin (type 1, type 2 or gestational diabetes)
    • infants of a woman with diet controlled diabetes (pre-existing or gestational)
  • early, frequent oral feeding (preferably breast milk)
  • glucose infusion (4-6 mg/kg/min = 60-80 mL/kg/day 10 per cent glucose)
  • judicious use of glucagon. This can result in rebound neonatal hyperglycaemia and perpetuation of hyperinsulinism. However, it can be very useful in the interim where IV access is not readily achievable and the 'pushing' of feeds is inappropriate
  • avoid wide swings in infant blood glucose (may perpetuate hyperinsulinism and delay gluconeogenesis)
    • use of 'mini' boluses of glucose for hypoglycaemia (for example, 2 mL/kg 10 per cent dextrose)
    • higher concentrations of IV dextrose infusion if fluid restricted (> 12.5 per cent require central line insertion)
    • avoid high-calorie formula
  • measurement of serum calcium and magnesium
  • adequate oxygenation if baby has HMD (at increased risk of PPHN).

Long-term complications

Long-term complications for infants with a diabetic mother may include:

  • obesity
  • risk of subsequent overt diabetes
  • adverse neurodevelopment in 4 per cent of cases (may relate to maternal ketosis).

More information

References

  • Reece EA, Homko CJ. Infant of the diabetic mother. Seminars in Perinatology. 1994;18:459-69
  • Suevo DM. The infant of the diabetic mother. Neonatal Network. 1997;16:25-33
  • Tyrala EE. The infant of the diabetic mother. Obstetrics and Gynaecology Clinics of North America. 1996;23:221-41
  • Cordero L, London MB. Infant of the diabetic mother. Clinics in Perinatology. 1993;20:635-48
  • Taeusch HW, Ballard RA (Eds). Avery's Diseases of the Newborn 7th Ed. W.B. Saunders Company, Philadelphia. 1998

Recommended reading

  • Suevo DM. The infant of the diabetic mother. Neonatal Network. 1997;16:25-33
  • Tyrala EE. The infant of the diabetic mother. Obstetrics and Gynaecology Clinics of North America. 1996;23:221-41 Updated 01/10/2011

Get in touch

Maternity and Newborn Clinical Network
Safer Care Victoria

Version history

First published: March 2016

Last web update: May 2016

Review by: March 2019

Uncontrolled when downloaded

Page last updated: 21 Nov 2018

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