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Diabetes in pregnancy
GDM screening, diagnosis, targets and timing of birth.
Source: NICE NG3 Calculator
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GDM risk factors (offer OGTT)
- BMI >30
- Previous baby ≥4.5 kg
- Previous GDM
- First-degree relative with diabetes
- Family origin with high diabetes prevalence (e.g. South Asian)
Diagnosis (75 g OGTT)
| Fasting | ≥5.6 mmol/L |
|---|---|
| 2 hour | ≥7.8 mmol/L |
| When | 24–28 wk; previous GDM: early then again at 24–28 wk. |
Targets
| Fasting | <5.3 mmol/L |
|---|---|
| 1 h after meal | <7.8 mmol/L |
| 2 h after meal | <6.4 mmol/L |
| In labour | 4–7 mmol/L hourly |
Treatment
| Fasting <7.0 | Diet & exercise 1–2 weeks → metformin → insulin. |
|---|---|
| Fasting ≥7.0 | Insulin immediately ± metformin. |
Birth
| Type 1 / 2 | 37+0 to 38+6 weeks. |
|---|---|
| GDM | No later than 40+6. |
| After GDM | Stop treatment at birth; fasting glucose at 6–13 weeks, then annual HbA1c. |
A summary for trained clinicians. Always check the full guideline, the patient in front of you and your hospital's protocol. Spotted an error? Tell us.