preconception advice/care for women with diabetes

Last reviewed 05/2023

Preconception advice has been outlined by NICE (1):

• women with diabetes who are planning to become pregnant should be advised:
  • that the risks associated with pregnancies complicated by diabetes increase with the duration of diabetes
• to use contraception until good glycaemic control (assessed by HbA1c ) has been established
• that glycaemic targets, glucose monitoring, medications for diabetes (including insulin regimens for insulin-treated diabetes) and medications for complications of diabetes will need to be reviewed before and during pregnancy
• that additional time and effort is required to manage diabetes during pregnancy and that there will be frequent contact with healthcare professionals. Women should be given information about the local arrangements for support, including emergency contact numbers
  
  
• dietary advice, weight and exercise
  • women with diabetes who are planning to become pregnant should be offered individualised dietary advice
  • women with diabetes who are planning to become pregnant and who have a body mass index above 27 kg/m2 should be offered advice on how to lose weight
  • women with diabetes who are planning to become pregnant 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
    
    

• target blood glucose and HbA1c levels in the preconception period

  • agree individualised targets for self-monitoring of blood glucose with women who have diabetes and are planning to become pregnant, taking into account the risk of hypoglycaemia
    
    
  • advise women with diabetes who are planning to become pregnant to aim for the same capillary plasma glucose target ranges as recommended for all people with type 1 diabetes
    
    
  • advise women with diabetes who are planning to become pregnant to aim to keep their HbA1c level below 48 mmol/mol (6.5%), if this is achievable without causing problematic hypoglycaemia
    
    
  • reassure women that any reduction in HbA1c level towards the target of 48 mmol/mol (6.5%) is likely to reduce the risk of congenital malformations in the baby
    
    
  • strongly advise women with diabetes whose HbA1c level is above 86 mmol/mol (10%) not to get pregnant because of the associated risks
  
  
• monitoring blood glucose and ketones in the pre-conception period
  • women with diabetes who are planning to become pregnant should be offered monthly measurement of HbA1c
  • women with diabetes who are planning to become pregnant should be offered a meter for self-monitoring of blood glucose
  • women with diabetes who are planning to become pregnant and who require intensification of hypoglycaemic therapy should be advised to increase the frequency of self-monitoring of blood glucose to include fasting and a mixture of pre- and postprandial levels
  • women with type 1 diabetes who are planning to become pregnant should be offered ketone testing strips and advised to test for ketonuria or ketonaemia if they become hyperglycaemic or unwell
    
    
• safety of medications for diabetes before and during pregnancy
  • women with diabetes may be advised to use metformin (see notes below) 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
  • the rapid-acting insulin analogues (aspart and lispro) are safe to use during pregnancy
  • women with insulin-treated diabetes who are planning to become pregnant should be informed that there is insufficient evidence about the use of long-acting insulin analogues during pregnancy. Therefore isophane insulin (also known as NPH insulin) remains the first choice for long-acting insulin during pregnancy
  • angiotensin-converting enzyme inhibitors and angiotensin-II receptor antagonists should be discontinued before conception or as soon as pregnancy is confirmed. Alternative antihypertensive agents suitable for use during pregnancy should be substituted
  • statins should be discontinued before pregnancy or as soon as pregnancy is confirmed
    
    
• retinal assessment in the pre-conception period
  • women with diabetes seeking pre-conception care should be offered retinal assessment at their first appointment (unless an annual retinal assessment has occurred within the previous 6 months) and annually thereafter if no diabetic retinopathy is found
    
    
• renal assessment in the pre-conception period
  • women with diabetes should be offered a renal assessment, including a measure of microalbuminuria, before discontinuing contraception. If serum creatinine is abnormal (120 micromol/litre or more) or the estimated glomerular filtration rate (eGFR) is less than 45 ml/minute/1.73 m2, referral to a nephrologist should be considered before discontinuing contraception

• renal assessment in the preconception period

  • offer women with diabetes a renal assessment, including a measure of low-level albuminuria (microalbuminuria), before discontinuing contraception
    
    • if serum creatinine is abnormal (120 micromol/litre or more), the urinary albumin:creatinine ratio is greater than 30 mg/mmol or the estimated glomerular filtration rate (eGFR) is less than 45 ml/minute/1.73m2, referral to a nephrologist should be considered before discontinuing contraception

Notes:

• NICE state with respect to the use of metformin in pregnancy:
  • metformin is used in UK clinical practice in the management of diabetes in pregnancy and lactation. There is strong evidence for its effectiveness and safety, which is presented in the full version of the guideline (1) . This evidence is not currently reflected in the SPC (February 2015). The SPC advises that when a patient plans to become pregnant and during pregnancy, diabetes should not be treated with metformin but insulin should be used to maintain blood glucose levels. Informed consent on the use of metformin in these situations should be obtained and documented

Reference:

• (1) NICE (February 2015). Diabetes in pregnancy: management of diabetes and its complications from preconception to the postnatal period