diagnosis of gestational diabetes

Last reviewed 05/2023

NICE (1) suggest testing criteria for gestational diabetes as:

• use the 2-hour 75 g oral glucose tolerance test (OGTT) to test for gestational diabetes in women with risk factors (see below)
  
  
• offer women who have had gestational diabetes in a previous pregnancy:
  • early self-monitoring of blood glucose or
  • a 75 g 2-hour OGTT as soon as possible after booking (whether in the first or second trimester), and a further 75 g 2-hour OGTT at 24-28 weeks if the results of the first OGTT are normal
    
    
• offer women with any of the other risk factors for gestational diabetes a 75 g 2-hour OGTT at 24-28 weeks (see below)
  
  

• glycosuria detected by routine antenatal testing

  • be aware that glycosuria of 2+ or above on 1 occasion or of 1+ or above on 2 or more occasions detected by reagent strip testing during routine antenatal care may indicate undiagnosed gestational diabetes. If this is observed, consider further testing to exclude gestational diabetes

• risk factors for gestational diabetes:
  • BMI above 30 kg/m2
  • previous macrosomic baby weighing 4.5 kg or above
  • previous gestational diabetes
  • family history of diabetes (first-degree relative with diabetes)
  • minority ethnic family origin with a high prevalence of diabetes
    
    
• diagnosis of gestational diabetes
  • diagnose gestational diabetes if the woman has either:
    
    
    • a fasting plasma glucose level of 5.6mmol/litre or above or
      
      
    • a 2-hour plasma glucose level of 7.8mmol/litre or above

Reference:

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