Gestational Diabetes Mellitus

Obs/Gynae

Glucose intolerance first recognised in pregnancy, increasing macrosomia, shoulder dystocia and neonatal hypoglycaemia risk.

Investigations

  • 75 g OGTT at 24–28 weeks (earlier if high risk)
  • Diagnostic: fasting ≥5.1, 1 h ≥10.0 or 2 h ≥8.5 mmol/L (IADPSG)
  • Growth scans, liquor volume

Management

  • Diet and exercise trial for 1–2 weeks
  • Metformin first-line pharmacotherapy; add or switch to insulin if targets missed
  • Targets: fasting <5.3, 1 h post-meal <7.8 mmol/L
  • Deliver by 40–41 weeks; earlier if macrosomia or poor control

Clinical pearls

  • Stop hypoglycaemic agents after delivery and check glucose
  • Postnatal OGTT/HbA1c at 6–13 weeks then annual screening — 50% develop T2DM within 10 years

Related in WardRound

Educational — verify locally.

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