MBBS OSCE · Obstetrics & Gynaecology
OSCE — Gestational Diabetes Mellitus
Eight-minute OSCE station on Gestational Diabetes Mellitus: focused history, examination priorities, investigations, emergency and definitive management.
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Brief (to candidate)
You will assess a patient with a presentation consistent with Gestational Diabetes Mellitus.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.
Clinical context
Gestational diabetes mellitus (GDM) is any degree of glucose intolerance with onset or first recognition during pregnancy (typically 24 to 28 weeks), excluding overt diabetes detectable at booking. Pathogenesis: placental anti-insulin hormones (hPL, cortisol, progesterone, prolactin, growth hormone, oestrogen) plus TNF-alpha drive progressive insulin resistance; pancreatic beta-cells fail to compensate. Risk factors: BMI over 30, age over 35, South Asian/Black/Hispanic ethnicity, previous GDM or macrosomia, family history, PCOS. Diagnosis: universal 75 g 2-hour OGTT at 24 to 28 weeks. Management: lifestyle (medical nutrition therapy, exercise) first; metformin then insulin to targets (fastin
Candidate tasks
- Clarify onset, severity, associated features, and red-flag symptoms.
- State focused examination priorities.
- List first-line investigations and any named score/criteria.
- Give immediate resuscitation steps.
- Outline definitive management with doses/routes where standard.
- Name complications and disposition (ward / HDU / theatre / discharge safety-net).
- Mention one special-population modifier (pregnancy, child, elderly, CKD).
Examiner checklist
| Domain | Pass behaviours |
|---|---|
| Definition | Correct working diagnosis language |
| Assessment | Focused, prioritised, red flags sought |
| Investigations | Appropriate first-line + interpretation |
| Emergency care | ABC / time-critical actions first |
| Definitive care | Specific drugs/procedures, not generic phrases |
| Safety | Booking HbA1c over 6.5% or fasting glucose over 7.0 mmol/L = OVERT (pre-gestatio |
| Safety | GDM with persistent hyperglycaemia despite lifestyle (fasting over 5.3, 1-h post |
| Safety | Macrosomia (EFW over 4.5 kg) — shoulder dystocia risk; offer elective caesarean |
| Communication | Clear plan and safety-netting |
Model outline
Lead with the working diagnosis and life threats. Resuscitate before definitive tests when unstable. Use guideline-standard therapy with named agents and doses. Document escalation criteria and follow-up. A safe candidate is specific, structured, and never delays critical care for non-urgent imaging.