There is a strong association between maternal hyperglycaemia and poor outcome. Fortunately, intervention can reduce the risk of large babies, shoulder dystocia, pre-eclampsia and caesarian section.
The key components of treatment are nutritional therapy and exercise and insulin if the glycaemic targets cannot be achieved.

The currently recommended targets for treatment are:

• fasting BSL less than 5.5 mmol/L
• postprandial BSL less than 8 mmol/L at 1 h or less than 6.7 mmol/L at 2 h

1. Medical nutritional therapy
Women need an individualised food plan distributed to promote optimal glycaemic control and avoid hypoglycaemia and ketonaemia.
Factors to consider are:

• the appropriate calorie level(energy intake is based BMI group, physical activity level, fetal growth pattern and the need to prevent excess maternal weight gain)
• adequate consumption of protein, fats, micronutrients and digestible carbohydrates
• a balanced nutrient intake high in fibre and food from all food groups, and
• consumption of unsaturated fatty acids, limiting saturated fats to less than 10% of energy intake and minimising of trans fats.

2. Exercise
Women should aim for moderate activity for a minimum 30 minutes on most days. An example is walking 2.5 to 5 km at 5 km/h.

The contraindications to exercise are significant heart disease, restrictive lung disease, incompetent cervix, multiple pregnancy at risk for preterm delivery, persistent second or third trimester bleeding, premature labour or premature rupture of membranes, and preeclampsia or uncontrolled hypertension.

Relative contraindications are haemoglobin < 10g/dL, extreme obesity, heavy cigarette consumption, previous preterm delivery, and poorly controlled seizure disorder or hyperthyroidism.

3. Oral hypoglycaemic agents
Metformin will control BSL in about 60% of women BUT it crosses the placenta and caution is needed until long-term follow-up studies have been done.

Glyburide also crosses the placenta and potentially stimulates already stressed β-islet cells. Long-term studies are required for both neonates and mothers and existing studies have not had sufficient power to determine fetal/neonatal outcomes.

4. Delivery
Delivery is at full-term unless there is macrosomia (expected birth weight >90th centile), poor glycaemic control, polyhydramnios or other obstetric indications, such as preeclampsia or antepartum haemorrhage.
An elective caesarean section is planned if the estimated fetal weight is >4 kg.

5. Postpartum care
Glucose tolerance returns to pre-pregnancy status within days of delivery but follow-up testing is advisable as 50% of women will develop type 2 DM within 10–15 years:

• GTT should be done at 6–8 weeks. This is repeated yearly if there is IGT or IFG or second yearly during the child-bearing years if it is normal, and
• GTT during pre-pregnancy planning or immediately a pregnancy is diagnosed to exclude type 2 DM.

Editor Dr Ramesh Manocha
Source: Dr Jeremy Oats, Annual Women’s Health Update, Melbourne 2010