Glucose Variability in Pregnancy Complicated by Diabetes
Condition: Gestational Diabetes; Continuous Glucose Monitoring; Glycemic Variability
MeSH terms: Diabetes, Gestational; Diabetes Mellitus
Study type: Observational

Summary: 
      Continuous glucose monitoring (CGM) methods provide details of magnitude and duration of
      glucose fluctuations, giving a unique insight on daily blood sugar control. Limited data are
      available on glucose variability (GV) in pregnancy. The aim of this study was to assess GV in
      normal pregnant women and cases of type 1 diabetes mellitus or gestational diabetes (GDM),
      and its possible association with HbA1c.
    

Detailed description: 
      Recent evidence in the literature suggests that glucose variability, characterized by extreme
      glucose excursions, may overlap with HbA1c levels in determining the risk of diabetes-related
      complications. Fluctuating blood glucose levels prompt an increase in free radicals and
      endothelial dysfunction, which are the links between hyperglycemia and the activation of
      pathological pathways that lead to tissue damage. Reece and Homko postulated an association
      between maternal hyperglycemia-induced oxygen free radical overproduction and fetal
      abnormalities, with the onset of diabetes-related embryopathy.Numerous studies have
      demonstrated that macrosomia and congenital malformations relate to glycemic control. In one
      study, 48-hour continuous glucose monitoring (CGM) of diurnal glucose profiles in pregnant
      women with type 1 diabetes was more sensitive than HbA1c alone in identifying an increased
      risk of offspring with congenital malformations. Such studies give the impression that
      transient hyperglycemic spikes in pregnant patients with diabetes can cause a high incidence
      of fetal overweight, regardless of whether or not the mother has chronic hyperglycemia.
      Glucose variability is still a factor that has been inadequately studied in pregnancies
      complicated by diabetes, and little is known about its relationship with maternal-fetal
      outcomes.A number of studies have demonstrated the utility of CGM for monitoring diabetes in
      pregnancy , but none have focused the attention on the importance of glucose fluctuations
      during gestation. Meanwhile, there has been a rapid increase in the number of new glucose
      variability indicators considered, although none of them seems to be definitively reliable.

      A better understanding of the pattern of blood glucose fluctuations in all the three
      trimesters of pregnancy, could help us to optimize glycemic control in pregnant women with
      diabetes.

      The aim of this study was therefore to assess glucose variability throughout the three
      trimesters of pregnancy in healthy women and in cases of type 1 diabetes mellitus or
      gestational diabetes, identifying the more representative and useful indicators of glucose
      fluctuations, to provide more accurate clinical informations along with HbA1c and beyond.
    

Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        Outpatient pregnant women enrolled at three Italian diabetes clinics (Padua, Pisa and
        Florence)
      
Keywords: diabetes; pregnancy; glucose variability; continuous glucose monitoring (CGM); gestational diabetes mellitus (GDM)