Diabetes, Guidelines for the Management of Diabetes Mellitus during Pregnancy and Diagnosis of Gestational Diabetes (1136)

INTRODUCTION

Type 1 diabetes in pregnancy is a high-risk state for both the woman and her fetus. Rates of miscarriage, perinatal loss and major congenital malformation are increased at least two to threefold.

Type 2 diabetes is becoming more common in this age group and management of pregnancies in people with type 2 diabetes should follow the same intensive program of metabolic, obstetric and neonatal supervision.

AIM

An optimal outcome may be obtained in diabetic pregnancy if excellent glycaemic control is achieved before and during pregnancy. Good pre-pregnancy planning is thus essential. Effective contraception, allowing a planned pregnancy, is therefore important.

CONTRACEPTION

Contraception should be discussed on an individual basis with all women of childbearing age with diabetes. In general, the contraceptive advice for a diabetic woman should follow that in the general population but with the following caveats:

• The combined OCP should be avoided in women with complications or risk factors for vascular disease or over 35 years of age. Progesterone-only preparations may be suitable in these women.
• Women using the intrauterine contraceptive device should be advised that they might be at increased risk of infection.

In women with complications or vascular risk a value judgement must be made which balances the risk of complications with the need to avoid pregnancy. The levonorgestrel releasing intrauterine device (e.g. Mirena coil) may be particularly suited as it is as effective as sterilisation and produces low circulating hormone levels.

PRE-PREGNANCY CARE

Infants whose mothers receive dedicated multidisciplinary pre-pregnancy counselling show significantly fewer major congenital malformations (approximating to the rate in non diabetic women) compared to infants of non-attendees. They also have fewer immediate problems and are kept in special care for shorter periods.

All women with diabetes who are planning a pregnancy should be seen at a Multidisciplinary Clinic involving a endocrinologist, obstetrician, diabetes nurse specialist, and dietician. They should be seen with their partners if possible and provided with written information.

• Full medical, obstetric and gynaecological history.
• Check thyroid function.
• Review current medications.
• STOP: ACE Inhibitors, A2 Blockers, and Statins, Review anti diabetic medication and likely stop all but metformin and insulin. Women on other agents may need replacement with insulin. Contact the local Diabetes Secondary Clinic immediately as soon as pregnancy confirmed.
• Prescribe Folic Acid 5mg daily for at least 1-month pre conception and for 1st trimester.
• Screen for complications.
• Advice on diet and weight reduction if relevant and strongly discourage smoking and refer to smoking cessation if appropriate
• Educate on the importance of near normal glycaemia control.
• Instruct partners to recognise and treat hypo glycaemia with glucagon if necessary.
• Support improvements in glycaemic control including access to structured education where appropriate and consideration of optimal monitoring and insulin delivery.

Women who are well controlled and free from complications should take 1 month’s folic acid prior to stopping contraception and keep a record of periods. Others should spend additional time optimising control and having complications investigated and treated.

Women should perform a pregnancy test if there is a lapse of 5 weeks between periods and contact their Diabetes Specialist Nurse if positive.

ANTE-NATAL CARE

Care should be hospital based, from a multi-disciplinary team. Women generally attend every 2 to 4 weeks until 30 weeks and then every 1-2 weeks thereafter.

POST NATAL CARE

• Insulin requirements fall dramatically after delivery- reduce dose to pre-conception dose.
• In breast feeding mothers reduce this further and encourage higher blood sugars than pregnancy.
• Discuss contraception after delivery (usually prior to hospital discharge).
• All women should be reviewed at the clinic in 6 weeks.

TESTING FOR GESTATIONAL DIABETES

Detection and management of gestational diabetes reduces birth weight and some maternal adverse outcomes such as pre-eclampsia. Dietary management is the key first step in management.   Risk factors for selection of women to offer OGTT are based on those in the SIGN and NICE guidelines – with the exception that BMI>= 35kg/m² used (with the aim of reducing to 30kg/m² as per those guidelines in time).  Diagnostic criteria are based on the SIGN guideline. 

• Routine screening at first antenatal visit
  • At booking all women should be assessed for the presence of risk factors for gestational diabetes (see table 1).
  • All women with risk factors should have HbA1c measured.
    • In early pregnancy, levels of HbA1c≥48 mmol/mol, (or fasting glucose ≥7.0mmol/l , or random or two hour glucose after OGTT ≥11.1 mmol/l glucose) are diagnostic of diabetes and these women should be offered treatment pathways as per pre-existing diabetes
    • Levels of 42-47mmol/mol should be managed as per GDM pathway
      
      
• Routine screening later in pregnancy
  • Women with previous GDM are also offered 75g OGTT at 14-16 weeks
  • All women with risk factors, including previous GDM (see table 1) should be offered a 75 g OGTT at 24-28 weeks unless already diagnosed or monitoring.
    
    
• Non- routine screening if
  • glycosuria of 2+ or above on 1 occasion
  • glycosuria of 1+ or above on 2 or more occasions
  • Polyhydramnios
  • EFW ≥97th centile
    
    
• Before 35 weeks - measure random glucose and HbA1c and offer 75gOGTT. If HbA1c ≥42mmol/mol or random glucose ≥11.1mmol in later pregnancy then glucose may be very raised and contact DSM for review before OGTT.
  
  
  
• after 35 weeks
  • Offer glucose monitoring for 2-3 days to exclude hyperglycaemia with Diabetes Specialist Midwife. Contact details for each hospital below

DIAGNOSIS

SIGN 171 criteria are used for 75 g OGTT:

• fasting venous plasma glucose ≥5.3 mmol/l, OR
• one hour value ≥10.6 mmol/l (if measured), OR
• two hours after OGTT ≥9.0 mmol/l.

MANAGEMENT

Women with gestational diabetes should have access to dietary advice from a dietician as well as consideration of treatment with metformin and/or insulin if needed - starting either with referral to the local multidisciplinary clinic or under a protocol agreed by that clinic.

Women with frank diabetes by non-pregnant criteria (fasting venous glucose ≥7 mmol/l, random or two hour ≥11.1 mmol/l) should be managed within a multidisciplinary clinic as they may have type 1 or type 2 diabetes and be at risk of pregnancy outcomes similar to those of women with pre-gestational diabetes.

FOLLOW-UP

Women who have had GDM are at an increased of type 2 diabetes in later life. 

All women should be offered HbA1c through their GP at 3-4 months.

Access to specialist weight management services is available and women can self refer using the GG&C website: Community Weight Management Service

Contact details

For OGTT : this is ordered through Badger

For Diabetes Specialist Midwife (eg concerns that BG monitoring raised,  request monitoring after 35 weeks):

PRMU:    ggc.dsm-prm@ggc.scot.nhs.uk

Clyde:    ggc.dsm-clyde@ggc.scot.nhs.uk 

QEUH:    ggc.dsm-qeuh@ggc.scot.uk