How should I manage a patient diagnosed with gestational diabetes regarding diet and lifestyle modifications?

For a patient diagnosed with gestational diabetes, management primarily begins with diet and lifestyle modifications, with a strong emphasis on patient education and close monitoring NICE NG3.

• Initial Management with Diet and Exercise:

  Upon diagnosis, advise the woman about changes in diet and exercise NICE NG3. It is crucial to explain the implications of gestational diabetes for both her and the baby, highlighting that good blood glucose control throughout pregnancy can reduce risks such as fetal macrosomia, birth trauma, induction of labour, caesarean section, neonatal hypoglycaemia, and perinatal death NICE NG3.

  • Dietary Advice: Advise a healthy diet, specifically recommending a switch from high to low glycaemic index foods NICE NG3. All women with gestational diabetes should be referred to a dietitian for tailored advice NICE NG3. Medical nutrition therapy is a cornerstone of gestational diabetes management, aiming to achieve optimal glycaemic control and improve maternal and fetal outcomes Cheong et al. 2025. While specific dietary patterns like those including colourful fruits and vegetables have shown potential benefits in managing gestational diabetes, the primary focus remains on overall healthy eating and glycaemic control Jaworsky et al. 2023.
  • Exercise Advice: Encourage regular exercise, such as walking for 30 minutes after a meal NICE NG3.
• Blood Glucose Monitoring:

  Teach women how to self-monitor their blood glucose levels NICE NG3. For those managing diabetes with diet and exercise changes alone, advise testing fasting and 1-hour post-meal blood glucose levels daily NICE NG3. The target capillary plasma glucose levels, if achievable without problematic hypoglycaemia, are: fasting below 5.3 mmol/litre, and either 1 hour after meals below 7.8 mmol/litre or 2 hours after meals below 6.4 mmol/litre NICE NG3. Individualised targets should be agreed upon, considering the risk of hypoglycaemia NICE NG3. Women taking insulin should aim to maintain capillary plasma glucose above 4 mmol/litre NICE NG3.

• Escalation of Treatment:

  If blood glucose targets are not met with diet and exercise changes within 1 to 2 weeks, metformin should be offered NICE NG3. If metformin is contraindicated or unacceptable, insulin should be offered NICE NG3. If targets are still not met with diet and exercise plus metformin, insulin should be offered as well NICE NG3. For women diagnosed with a fasting plasma glucose level of 7.0 mmol/litre or above, immediate treatment with insulin (with or without metformin) should be offered alongside diet and exercise changes NICE NG3. Similarly, for those with a fasting plasma glucose between 6.0 and 6.9 mmol/litre and complications like macrosomia or hydramnios, immediate insulin (with or without metformin) and diet and exercise changes should be considered NICE NG3.

• Further Management Considerations:

  When diagnosed, women should be offered a review with the joint diabetes and antenatal clinic within 1 week NICE NG3. It is also important to measure HbA1c levels at diagnosis to identify women who may have pre-existing type 2 diabetes NICE NG3.