Diabetes in Pregnancy


Gestational diabetes mellitus (GDM) is any degree of glucose intolerance first recognised in pregnancy.

If inadequately managed, GDM is associated with increased risk of perinatal morbidity and mortality.

Diagnosis and prompt institution of therapy reduce the risks of poor outcomes

Screening for GDM


  • Between 24 and 28 weeks of gestation


Women with:

  • High risk for GDM
  • BMI 25 kg/m²
  • Previous history of GDM
  • Glycosuria
  • Previous large baby (>4 kg)
  • Poor obstetric history
  • Family history of diabetes
  • Known IGT/IFG


  • Combined health care team- obstetrician, diabetologist, diabetes educator, and paediatrician/ neonatologist
  • Initial therapy is dietary modification
  • Spread carbohydrate over 3 small to moderate sized meals and 2 3
  • Consider an evening snack to prevent starvation ketosis
  • Energy intake should provide for
    desirable weight gain during pregnancy
  • For obese women a 30- 33% calorie restriction is advised
  • Daily SBGM (urine glucose monitoring) is not useful in pregnancy
  • Initiate insulin therapy if:
    • Fasting plasma glucose is > 5.8 mmol/L
    • 1 hour post-prandial glucose is > 8.6 mmol/L
    • 2 hour post-prandial plasma glucose is >7.5 mmol/L
  • Modify insulin regimen to achieve above targets
  • Regular assessment of maternal wellbeing should include blood pressure and urine protein
  • Regular surveillance for foetal well
  • Delivery at 38 weeks gestation recommended
  • Withdraw therapy for diabetes after birth
  • Re-assess classification of maternal status at 6 weeks post partum
  • Acute metabolic complications of diabetes mellitus (see emergency section)

Differential diagnoses

  • Trauma
  • Stroke
  • Seizures
  • Drug overdose
  • Ethanol intoxication

Prevention of diabetes

  • Generalised obesity, central obesity and physical inactivity are the major modifiable risk factors, and should be avoided/corrected
  • Onset of diabetes can be delayed in people at high risk by active lifestyle modification

Lifestyle modification should be the
cornerstone of preventative strategies in the following categories of people:

  • Age > 45years
  • Overweight and obesity (BMI> 25 kg/mm)
  • Physical inactivity
  • First degree relatives with diabetes
  • Previous gestational diabetes
  • Previously identified IGT or IFG
  • Dyslipidaemia
  • Hypertension

The components of lifestyle modification
should include (but not be limited to) the

  • Lose 5-10% weight
  • Reduce fat intake (< 30% of total daily calories)
  • Reduce saturated fat intake (< 10% of total daily calories)
  • Increase fibre intake to > 15 g/1000 kcal
  • Traditional African diets are high in fibre content.
  • Increase levels of physical activity e.g. brisk walking producing a heart rate >150/min
  • Exercise should last for at least 30
    minutes and should be undertaken at least three times a week
  • Reduce high alcohol intake

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