These recommendations are to be used in conjunction with usual obstetric practice – they are specific to the additional requirements that diabetes imposes.

Antenatal care

Women with diabetes (and their partner) should be included as members of the team, be involved in decisions about their care and be offered the opportunity to make choices by provision of appropriate and sufficient information. At the earliest possible time, women with diabetes should be seen in a combined clinic by a team that should include an obstetrician with a special interest in diabetes and pregnancy, a physician, a specialist diabetes dietitian, a specialist diabetes nurse and a specialist midwife. It may be necessary to arrange appointments every two weeks, depending on the needs of the individual woman.

Blood glucose levels should be monitored frequently and insulin adjusted (including the frequency of injections) to achieve a near normal HbA1c and pre/ post prandial blood glucose levels of:

Before meals              capillary whole blood glucose                                          less than 5.6 mmol/l

                                    capillary plasma glucose                                                4.4-6.1 mmol/l

Two hours after            capillary whole blood glucose                            less than 7.8 mmol/l

meals                            capillary plasma glucose                                                less than 8.6 mmol/l

Goals should be set with the woman for self-monitored glucose, having established that the woman can use her blood glucose meter to produce results that are +/-0.5 mmol/l when compared to a reference technique. Such quality assurance methods should be available through the hospital laboratory.

 Diabetes UK realises that in addition each blood glucose monitoring system will vary by at least 10 per cent from a reference value. Individual meters will also vary from the method mean. These figures must therefore be interpreted locally and individually.

All blood glucose meters in the UK use whole blood to measure blood glucose levels. Some meters give the result in terms of whole blood glucose, others in terms of plasma glucose, which can be 12 per cent higher. For women with diabetes considering pregnancy achieving tight blood glucose control is vital. Diabetes UK suggests that this group is aware of the range their result will be in. They should contact their meter manufacturer to check which type of result their meter gives.                                                                                     

No insulins are currently licensed for use in pregnancy. Women on an established insulin regimen including analogue insulin should be able to continue.

As the risk of hypoglycaemia is increased, ensure that those close to the woman with diabetes have been instructed in the recognition, management and treatment of hypoglycaemia and partners should be supplied with and taught to use glucagon. As ketoacidosis is particularly dangerous in pregnancy, and is preventable, women should all be prescribed and instructed in the use of ketone testing strips. A fast-track system for referral and treatment for ketoacidosis should be available and be explained to pregnant women. The emphasis should be on prevention.

An experienced physician, ophthalmologist or optometrist should perform a detailed retinal examination on all patients during the first trimester and each trimester for those with retinopathy to detect and treat any accelerated retinopathy. Women with existing retinopathy are at an increased risk of retinopathy progressing during pregnancy.

An ultrasound measurement of the foetal crown-rump length should be made in the first trimester to confirm the duration of pregnancy. A detailed ‘anomaly’ ultrasound scan should be performed between 18 and 22 weeks and analysed by an experienced doctor.

Measurements of the head/abdominal circumference should be obtained to assess foetal growth. Cardiotocographs or biophysical profiles may be used from 36 weeks gestation to assess foetal well being in late pregnancy.

If delivery is indicated before 36 weeks, administration of corticosteroids should be given if indicated for pre-term delivery to prevent neonatal respiratory distress syndrome. Additional insulin must be given to prevent severe maternal hyperglycaemia and possible ketoacidosis.

With good diabetes control, in the absence of significant diabetic or other complications, it may be possible to prolong pregnancy to 39 or 40 weeks to achieve a vaginal delivery.

Intrapartum

Continuous foetal heart monitoring should be used during labour and foetal blood sampling should be available if indicated.

The aim during labour or caesarean section should be to maintain the maternal blood glucose between 4.0–6.0 mmol/l; usually with intravenous dextrose by constant infusion or multiple injections of short-acting insulin given with hourly capillary blood glucose monitoring. The mother should be allowed to self-monitor if she prefers. More research is needed to determine the best method to control glucose intrapartum.

Postpartum

Immediately after vaginal delivery, the insulin rate should be reduced by at least 50 per cent as rapid decline in insulin requirement occurs following delivery of the placenta.

After delivery most mothers need about their pre-pregnancy dose of insulin but those who breastfeed may need less. Breastfeeding should be encouraged and the baby offered a feed within the first hour of birth.

All women should have an opportunity to be reviewed by the multidisciplinary team.

The baby should remain with its mother and need only be admitted to the intensive care nursery if there is a specific medical indication.

The neonatal blood glucose should be measured regularly on a blood glucose analyser such as Haemacue™, which is designed for neonatal use.

Mothers should be offered contraceptive advice. They should be seen at six weeks postpartum by their GP or at a combined diabetes clinic.

Women with Type 2 diabetes

Type 2 and Gestational diabetes are particularly common in women of Asian or African Caribbean origin.

Women with Type 2 diabetes should be seen pre-pregnancy in a similar way to those with Type 1 diabetes. If they are on oral hypoglycaemic agents or if their HbA1c is above normal they should be started on insulin before conception. Their oral hypoglycaemic therapy should be stopped. Those not attending for pre-pregnancy counselling should be started on insulin as early as possible if preprandial blood glucose levels exceed 6.0mmol/l, or if HbA1c is elevated (there is no place for oral agents in early pregnancy and these should be stopped as soon as pregnancy is confirmed). Management should then be as for women with Type 1 diabetes.

Gestational diabetes (diabetes first diagnosed during pregnancy)

There is uncertainty, confusion and no consensus on the subject of screening and diagnosis of Gestational diabetes. These guidelines attempt to take a balanced non-doctrinaire approach that can be adapted locally and may change, as new information becomes available. Treatment recommendations are based on the Diabetic Pregnancy Study Group of the European Association for the Study of Diabetes.

Screening

Urine should be tested for glucose at every antenatal visit (this ensures that the small group of women developing Type 1 during pregnancy will not be missed). If positive casual timed plasma venous glucose estimation should be performed and interpreted as below.

A 75g OGTT should be performed if the random plasma venous glucose concentrations are not diagnostic but are if:

greater than 6.1mmol/l in the fasting state or more than two hours after food or

greater than 7.0mmol/l within two hours of food.

Diagnosis

Criteria for diagnosis are based on the World Health Organisation’s (WHO) recommendations for diagnosis of Gestational diabetes. Diagnosis should be made if the fasting venous plasma glucose is greater than 7.0mmol/l or a fasting venous plasma glucose is less than 7.0mmol/l but with a venous plasma glucose two hours after a 75g glucose load greater than 7.8mmol/l.

Diabetes UK endorses the use of the WHO definition to allow for comparative studies. However, since glucose tolerance changes with the duration of pregnancy, the gestation at which the diagnosis was made should be recorded and, if made in the third trimester, the clinician should be cautious about the clinical implications of impaired glucose tolerance. Some concern has been raised about the level at which intensive treatment is necessary. Treatment, such as dietary and lifestyle advice, should be provided for all women with Gestational diabetes. More intensive treatment will need to be given at the discretion of the individual medical team. However, it is clear that if the two-hourly OGTT value is over 9.0 mmol/l the woman will need intensive treatment.

Management principles

Dietary advice including redistribution of meals, to ensure a regular intake of low glycaemic index carbohydrates across the day, restriction of saturated fat and sugar, and cautiously reducing calories if overweight. Appropriate exercise should be encouraged. Blood glucose monitoring should be carried out. If the pre-prandial levels exceed 6.0mmol/l the mother may need to be treated with insulin.

Obstetric management should be individualised, most pregnancies can continue to 40 weeks

Monitoring

The woman should be encouraged to perform daily blood glucose monitoring similar to that described above. For women treated with insulin, limited evidence indicates that postprandial monitoring is superior to preprandial monitoring. Postprandial versus preprandial blood glucose monitoring in women with Gestational diabetes mellitus requiring insulin therapy.

Blood pressure and urine protein monitoring is needed to detect hypertensive disorders.

When fasting glucose levels exceed 5.9 mmol/l or pregnancy progresses past term there should be increased obstetric surveillance because of the risk of stillbirth. Assessment of foetal growth by ultrasonography for asymmetrical growth may help identify foetuses that can benefit from maternal insulin therapy. This is particularly useful in the early third trimester.

Management

All women with Gestational diabetes (GDM) should receive dietary advice, by a specialist dietitian when possible. The diet should give adequate calories and nutrients to meet the needs of pregnancy and should be consistent with the maternal blood glucose goals that have been established. Noncaloric sweeteners may be used in moderation.

For obese women (BMI greater than 30), a 30–33% calorie restriction reduces hyperglycaemia and plasma triglycerides without increasing ketonuria.  Restriction of carbohydrates to 35–40% of calories decreases maternal glucose levels and improves maternal and foetal outcomes.

Insulin is usually used to reduce glucose levels and hence maternal or foetal problems. It should be considered if glucose levels are high or if foetal growth is abnormal. Evidence suggests that insulin should be commenced if:

capillary fasting whole blood glucose is greater than 5.3 mmol/l, or plasma glucose greater than 5.8 mmol/l or1hourly postprandial whole blood glucose greater than 7.8 mmol/l (plasma glucose greater than 8.6 mmol/l).

Foetal abdominal circumference measurement early in the third trimester can identify infants with no excess risk of macrosomia even in the absence of maternal insulin therapy. This approach has been tested primarily in pregnancies with maternal fasting serum glucose levels of less than 5.8 mmol/l.

Blood glucose results should guide the doses, timing and type of insulin needed. 

Oral glucose-lowering agents have generally not been recommended during pregnancy. However, one randomised, unblinded clinical trial compared the use of insulin and glibenclamide in women with GDM who were not able to meet their glycaemic targets. Treatment with either agent resulted in similar perinatal outcomes. All patients were beyond the first trimester of pregnancy at the initiation of therapy. Further studies are needed in a larger patient population to establish its safety, but this option should be discussed with the patient.

GDM is a potential indication for caesarean delivery if foetal macrosomia is present. Prolonging gestation past 38 weeks increases the risk of foetal macrosomia without reducing caesarean rates, so that delivery during the 38th week is recommended unless there are other obstetric considerations.

Postpartum

Insulin can usually be stopped immediately postpartum. Breast-feeding, as always, should be encouraged in women with GDM.

Women with Gestational diabetes should have the opportunity to be seen by the multidisciplinary team, as with Type 1 and Type 2 patients. They should be advised of: the increased risk of Type 1 and Type 2 diabetes; that Type 2 diabetes can be reduced by exercise and avoidance of obesity; and of the increased risk of Gestational diabetes in subsequent pregnancies. They should also be referred to the specialist diabetes team and be advised to make any appropriate dietary changes early in any subsequent pregnancy, preferably before conception. Women with Gestational diabetes should be encouraged to take advantage of Well Women Clinics and attend for regular healthchecks.

Six weeks after delivery a 75g OGTT should be carried out and results interpreted according to WHO criteria. For further information see Position statement: Early identification of people with Type 2 diabetes at www.diabetes.org.uk/infocentre/state/early/htm.

Women who have an abnormal result should be treated accordingly and those with normal glucose tolerance should be told about the high risk of developing diabetes in the future. The measures they can take to avoid developing diabetes should be discussed.