For women diagnosed with gestational diabetes, offer a 75-g 2-hour oral glucose tolerance test (OGTT) to confirm diagnosis if not already done, using thresholds of a fasting plasma glucose level of 5.6 mmol/litre or above or a 2-hour plasma glucose level of 7.8 mmol/litre or above NICE NG3.
Once diagnosed, provide education on the implications for mother and baby, emphasizing that good blood glucose control reduces risks such as macrosomia, trauma during birth, neonatal hypoglycaemia, and perinatal death NICE NG3.
Advise women to manage their blood glucose with diet and exercise initially, including a healthy diet and switching to low glycaemic index foods, and refer to a dietitian NICE NG3.
Encourage regular physical activity, such as walking for 30 minutes after meals NICE NG3.
Self-monitoring of blood glucose should be taught, aiming for target levels of fasting <5.3 mmol/litre and 1-hour post-meal <7.8 mmol/litre, or 2-hours post-meal <6.4 mmol/litre, tailored to individual risk and hypoglycaemia risk NICE NG3.
If blood glucose targets are not met with diet and exercise alone, consider pharmacological treatment, starting with metformin; if contraindicated or unacceptable, offer insulin. If targets are still not achieved, combine insulin with metformin NICE NG3.
Timing of birth should be planned, with delivery ideally no later than 40 weeks plus 6 days, and consider induction or caesarean if indicated NICE NG3.