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Gestational diabetes mellitus is a condition in which a pregnant mother, without pre-existing diabetes, develops high blood sugar levels during pregnancy. The two subtypes of gestational diabetes are:

  • Type A1: abnormal oral glucose tolerance test (GTT), but normal blood glucose levels during fasting and two hours after meals – diet modification is enough to control glucose levels
  • Type A2: abnormal GTT with abnormal glucose levels during fasting and/or after meals – additional therapy with insulin or other medications is required.

 Risk factors for gestation diabetes mellitus:

  • Maternal age >35 years old
  • First degree family history of Diabetes Mellitus
  • BMI > 25 kg/m2
  • Pre-existing conditions – polycystic ovarian disease
  • Ethnicity – asians are at highest risk
  • Excessive gestational weight gain

Medications:

Inj. Human Mixtard 70/30 (intermediate acting insulin – Isophane 70%; short acting insulin – Actrapid 30%) (use insulin syringe only) depending on the HbA1c:

  • HbA1c is less than 8 – 0.1 units/kg 30 mins before breakfast and 0.1 units/kg 30 mins before dinner
  • HbA1c between 8 and 10 – 0.2 units/kg 30 mins before breakfast and 0.2 units/kg 30 mins before dinner
  • HbA1c more than 10 – 0.3 units/kg 30 mins before breakfast and 0.3 units/kg 30 mins before dinner
  • Increase dose by 1 unit every 3 days until fasting blood glucose and post meal blood glucose targets are achieved
  • Check blood glucose – fasting, before rapid acting insulin blood glucose and at bedtime

Oral anti-diabetics such as metformin is often used however it is not universally recommended. Please use individual discretion and discuss with gynaecologist if needed.

Post-delivery plan:

  • Monitor blood sugars regularly.
  • Oral anti-diabetics are relatively contraindicated if mother is breast feeding.
  • Please refer to guidelines on type 1 or type 2 diabetes as applicable.

Investigations:

  • Glucose tolerance test (GTT)
  • Ante-natal profile – as advised by local and national guidelines

General advice:

  • Follow diabetic diet
  • Regular aerobic exercise regime

Referral:

Consider referral to diabetologist or endocrinologist if patients fail to respond to above treatment or presents with additional  complications.