Management of type 2 diabetes during pregnancy

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A summary of the NICE guidance relating to management of diabetes in pregnancy is presented below (1):

• target ranges for blood glucose during pregnancy
  • individualised targets for self-monitoring of blood glucose should be agreed with women with diabetes in pregnancy, taking into account the risk of hypoglycaemia
  • advise pregnant women with any form of diabetes to maintain their capillary plasma glucose below the following target levels, if these are achievable without causing problematic hypoglycaemia:
    • fasting: 5.3 mmol/litre and
      
      
    • 1 hour after meals: 7.8mmol/litre or 2 hours after meals: 6.4mmol/litre
      
      
    • if on insulin or glibenclamide then advise the women to maintain their capillary plasma glucose level above 4mmol/litre
      
      
• monitoring blood glucose and ketones during pregnancy
  • advise pregnant women with type 1 diabetes to test their fasting, pre-meal, 1-hour post-meal and bedtime blood glucose levels daily during pregnancy
  • pregnant women with type 2 diabetes or gestational diabetes who are on a multiple daily insulin injection regimen should be advised to test their fasting, pre-meal, 1-hour post-meal and bedtime blood glucose levels daily during pregnancy
  • advise pregnant women with type 2 diabetes or gestational diabetes to test their fasting and 1-hour post-meal blood glucose levels daily during pregnancy if they are:
    • on diet and exercise therapy or
    • taking oral therapy (with or without diet and exercise therapy) or single-dose intermediate-acting or long-acting insulin
  • consider continuous glucose monitoring for pregnant women on insulin therapy:
    • who have problematic severe hypoglycaemia (with or without impaired awareness of hypoglycaemia) or
    • who have unstable blood glucose levels (to minimise variability) or
    • to gain information about variability in blood glucose levels
  • ketone testing and diabetic ketoacidosis
    • offer pregnant women with type 1 diabetes blood ketone testing strips and a meter, and advise them to test for ketonaemia and to seek urgent medical advice if they become hyperglycaemic or unwell
    • advise pregnant women with type 2 diabetes or gestational diabetes to seek urgent medical advice if they become hyperglycaemic or unwell
    • test urgently for ketonaemia if a pregnant woman with any form of diabetes presents with hyperglycaemia or is unwell, to exclude diabetic ketoacidosis
      
      
• management of diabetes during pregnancy
  • women with diabetes should be advised to take folic acid (5 mg/day) until 12 weeks of gestation to reduce the risk of having a baby with a neural tube defect
  • women with diabetes may be advised to use metformin as an adjunct or alternative to insulin in the pre-conception period and during pregnancy, when the likely benefits from improved glycaemic control outweigh the potential for harm. All other oral hypoglycaemic agents should be discontinued before pregnancy and insulin substituted
    • note though that in the gestational diabetes part of the guideline NICE states that glibenclamide might also be used:
      • consider glibenclamide for women with gestational diabetes:
        • in whom blood glucose targets are not achieved with metformin but who decline insulin therapy or
        • who cannot tolerate metformin
  • healthcare professionals should be aware that the rapid-acting insulin analogues (aspart and lispro) have advantages over soluble human insulin during pregnancy and should consider their use
  • women with insulin-treated diabetes should be advised of the risks of hypoglycaemia and hypoglycaemia unawareness in pregnancy, particularly in the first trimester
  • use isophane insulin (also known as NPH insulin) as the first choice for long-acting insulin during pregnancy. Consider continuing treatment with long-acting insulin analogues (insulin detemir or insulin glargine) in women with diabetes who have established good blood glucose control before pregnancy
  • during pregnancy, women with insulin-treated diabetes should be provided with a concentrated glucose solution and women with type 1 diabetes should also be given glucagon; women and their partners or other family members should be instructed in their use
  • during pregnancy, women with insulin-treated diabetes should be offered continuous subcutaneous insulin infusion (CSII or insulin pump therapy) if adequate glycaemic control is not obtained by multiple daily injections of insulin without significant disabling hypoglycaemia
  • during pregnancy, women with type 1 diabetes who become unwell should have diabetic ketoacidosis excluded as a matter of urgency
    • women who are suspected of having diabetic ketoacidosis should be admitted immediately for level 2 critical care
      
      
• monitoring HbA1c
  • HbA1c levels should be measured in all pregnant women with pre-existing diabetes at the booking appointment to determine the level of risk for the pregnancy
  • consider measuring HbA1c levels in the second and third trimesters of pregnancy for women with pre-existing diabetes to assess the level of risk for the pregnancy
  • level of risk for the pregnancy for women with pre-existing diabetes increases with an HbA1c level above 48mmol/mol (6.5%)
  • measure HbA1c levels in all women with gestational diabetes at the time of diagnosis to identify those who may have pre-existing type 2 diabetes
    
    
• retinal assessment during pregnancy
  • offer pregnant women with pre-existing diabetes retinal assessment by digital imaging with mydriasis using tropicamide following their first antenatal clinic appointment (unless they have had a retinal assessment in the last 3 months), and again at 28 weeks. If any diabetic retinopathy is present at booking, perform an additional retinal assessment at 16-20 weeks
  • if retinal assessment has not been performed in the preceding 12 months, it should be offered as soon as possible after the first contact in pregnancy in women with pre-existing diabetes
  • diabetic retinopathy should not be considered a contraindication to rapid optimisation of glycaemic control in women who present with a high HbA1c in early pregnancy
  • women who have preproliferative diabetic retinopathy diagnosed during pregnancy should have ophthalmological follow-up for at least 6 months following the birth of the baby
  • diabetic retinopathy should not be considered a contraindication to vaginal birth
    
    
• renal assessment during pregnancy
  • If renal assessment has not been undertaken in the preceding 3 months in women with pre-existing diabetes, arrange it at the first contact in pregnancy. If the serum creatinine is abnormal (120 micromol/litre or more), the urinary albumin:creatinine ratio is greater than 30 mg/mmol or total protein excretion exceeds 2 g/day, referral to a nephrologist should be considered (eGFR should not be used during pregnancy). Thromboprophylaxis should be considered for women with proteinuria above 5 g/day (macroalbuminuria)
    
    
• screening for congenital malformations
  • women with diabetes should be offered antenatal examination of the four-chamber view of the fetal heart and outflow tracts at 20 weeks
    
    
• monitoring fetal growth and well-being
  • pregnant women with diabetes should be offered ultrasound monitoring of fetal growth and amniotic fluid volume every 4 weeks from 28 to 36 weeks
  • routine monitoring of fetal wellbeing (using methods such as fetal umbilical artery Doppler recording, fetal heart rate recording and biophysical profile testing) before 38 weeks is not recommended in pregnant women with diabetes, unless there is a risk of fetal growth restriction
  • women with diabetes and a risk of intrauterine growth restriction (macrovascular disease and/or nephropathy) will require an individualised approach to monitoring fetal growth and well-being
    
    
• timing and mode of birth
  • advise pregnant women with type 1 or type 2 diabetes and no other complications to have an elective birth by induction of labour, or by elective caesarean section if indicated, between 37+0 weeks and 38+6 weeks of pregnancy
  • consider elective birth before 37+0 weeks for women with type 1 or type 2 diabetes if there are metabolic or any other maternal or fetal complications
  • diabetes should not in itself be considered a contraindication to attempting vaginal birth after a previous caesarean section
  • pregnant women with diabetes who have an ultrasound-diagnosed macrosomic fetus should be informed of the risks and benefits of vaginal birth, induction of labour and caesarean section

Reference:

• (1) NICE (February 2015). Diabetes in pregnancy Management of diabetes and its complications from pre-conception to the postnatal period