Glucose Variability in Pregnancy Complicated by Diabetes

Glucose Fluctuations During Gestation: an Additional Tool for a Better Monitoring of Pregnancy Complicated by Diabetes

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.

Study Overview

• Status: Completed
• Conditions: Gestational Diabetes; Glycemic Variability; Continuous Glucose Monitoring

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.

• Study Type: Observational
• Enrollment (Actual): 50

Contacts and Locations

Study Locations

• Italy
  • Florence, Italy
    • Department of Gynecology, Perinatology and Human Reproduction, University of Florence
  • Padova, Italy
    • Department of Medicine, University of Padua
  • Pisa, Italy
    • Department of Endocrinology and Metabolic Diseases, University of Pisa

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

• Sampling Method: Non-Probability Sample

Study Population

Outpatient pregnant women enrolled at three Italian diabetes clinics (Padua, Pisa and Florence)

Description

Inclusion Criteria:

• diagnosis of type 1 diabetes or GDM
• able to become familiar with glucose monitoring methodologies

Exclusion Criteria:

• type 2 diabetes
• pre-gestational BMI > 35 Kg/m2
• HbA1c > 8% for type 1 diabetic pregnant women

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Type 1 diabetes; Pregnant women affected by type 1 diabetes mellitus
GDM; Pregnant women affected by gestational diabetes mellitus
Healthy; Healthy pregnant women

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glucose variability indexes during first, second and third trimester of pregnancy	Patients wore underwent continuous glucose monitoring for 2 days in each trimester of pregnancy. As indexes of glucose variability we considered: the mean amplitude of glucose excursion (MAGE); the total standard deviation (SD); the interquartile range (IQR); the continuous overlapping net glycemic action (CONGA1), calculated at 1 hour. The low blood glucose index (LBGI) and high blood glucose index (HBGI) were also calculated.	9 months

Secondary Outcome Measures

Outcome Measure	Time Frame
Association between HbA1c and glucose variability indicators in the three trimesters pf pregnancy, in the three groups of women	9 months

Collaborators and Investigators

• Sponsor: University of Padova
• Investigators: Study Chair: Annunziata Lapolla, MD, Department of Medicine, University of Padova

Publications and helpful links

General Publications

• Dalfra MG, Sartore G, Di Cianni G, Mello G, Lencioni C, Ottanelli S, Sposato J, Valgimigli F, Scuffi C, Scalese M, Lapolla A. Glucose variability in diabetic pregnancy. Diabetes Technol Ther. 2011 Aug;13(8):853-9. doi: 10.1089/dia.2010.0145.
• Kerssen A, de Valk HW, Visser GH. Forty-eight-hour first-trimester glucose profiles in women with type 1 diabetes mellitus: a report of three cases of congenital malformation. Prenat Diagn. 2006 Feb;26(2):123-7. doi: 10.1002/pd.1340.
• Di Cianni G, Miccoli R, Volpe L, Lencioni C, Del Prato S. Intermediate metabolism in normal pregnancy and in gestational diabetes. Diabetes Metab Res Rev. 2003 Jul-Aug;19(4):259-70. doi: 10.1002/dmrr.390.

Study record dates

Study Major Dates

• Study Start: January 1, 2004
• Primary Completion (Actual): March 1, 2005
• Study Completion (Actual): March 1, 2005

Study Registration Dates

• First Submitted: June 18, 2013
• First Submitted That Met QC Criteria: June 18, 2013
• First Posted (Estimate): June 21, 2013

Study Record Updates

• Last Update Posted (Estimate): June 21, 2013
• Last Update Submitted That Met QC Criteria: June 18, 2013
• Last Verified: June 1, 2013

More Information

Terms related to this study

• Keywords: diabetes; pregnancy; continuous glucose monitoring (CGM); glucose variability; gestational diabetes mellitus (GDM)
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Endocrine System Diseases; Pregnancy Complications; Diabetes Mellitus; Diabetes, Gestational
• Other Study ID Numbers: GES03