The Effect of a Low Glycemic Index Diet on Blood Sugar Control in Pregnant Women at Risk for Gestational Diabetes

Gestational diabetes mellitus (GDM) is a condition in which high blood sugar levels occur during pregnancy. GDM increases the risk of medical complications during pregnancy which may harm the mother and her baby. Since treating GDM to reduce blood sugar reduces the risk of harm, all pregnant women are screened for GDM using a glucose challenge test (GCT). We think that a diet containing low glycemic index foods could help keep blood sugar levels normal during pregnancy and therefore prevent GDM. Thus, the purpose of this study is to see if a diet containing low glycemic index foods will reduced blood sugar after the GCT and reduce the prevalence of GDM in women at high risk for the development of GDM.

Study Overview

• Status: Completed
• Conditions: Diabetes, Gestational
• Intervention / Treatment: Other: Nutrition education

• Study Type: Interventional
• Enrollment (Actual): 103
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5G 1X5
      • Mt Sinai Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• Attending Mt. Sinai Maternal Fetal Medicine Unit
• Any ONE of: body mass index >=25 kg/m^2
• OR age >=35 years
• OR high risk ethnicity (Asian, South Asian, Hispanic, African, Aboriginal)

Exclusion Criteria:

• Have pre-existing diabetes (type 1 or type 2) before becoming pregnant
• Acute or chronic illness which may affect carbohydrate metabolism
• Language/literacy barriers which cannot be overcome via available resources
• >16 weeks gestation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: High fiber; High fiber carbohydrate foods with a high / medium glycemic index. Whole wheat bread and/or brown rice are provided to subjects if they wish. Subjects are provided with a list of other recommended carbohydrate foods.	Other: Nutrition education; Group nutrition classes supplemented by handouts and provision of key study foods.
Active Comparator: Low GI; Carbohydrate foods with a low glycemic index. Low GI rice and whole grain bread provided to subjects if they wish. Subjects are provided with a list of recommended foods.	Other: Nutrition education; Group nutrition classes supplemented by handouts and provision of key study foods.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Serum glucose concentration 1hr after glucose challenge test	26 weeks gestation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
GCT outcome	ie. normal, borderline, abnormal	26 weeks gestation
GDM outcome	Presence or absence of gestational diabetes	26 weeks gestation
Maternal weight		At EACH of the following times: 12, 16, 20, 24, 28, 32, 36 and 40 weeks gestation
Mode of delivery	Normal or cesarean section	At time of birth of baby
Presence of birth trauma		At time of birth of baby
Weight of baby		At time of birth of baby
Presence of macrosomia		At time of birth of baby
presence of large for gestational age baby		At time of birth of baby
Presence of small for gestational age baby		At time of birth of baby
food frequency questionnaire		at 12 weeks and 26 weeks gestation
Acceptability of study foods		26 weeks gestation

Collaborators and Investigators

• Sponsor: University of Toronto
• Investigators: Principal Investigator: Thomas MS Wolever, BM, BCh, PhD, University of Toronto

Study record dates

Study Major Dates

• Study Start: March 1, 2010
• Primary Completion (Actual): June 1, 2011
• Study Completion (Actual): December 1, 2011

Study Registration Dates

• First Submitted: April 9, 2010
• First Submitted That Met QC Criteria: April 15, 2010
• First Posted (Estimate): April 16, 2010

Study Record Updates

• Last Update Posted (Estimate): March 12, 2013
• Last Update Submitted That Met QC Criteria: March 11, 2013
• Last Verified: March 1, 2013

More Information

Terms related to this study

• Keywords: Randomized clinical trial; Glycemic index; Carbohydrates; Gestational diabetes
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Endocrine System Diseases; Pregnancy Complications; Diabetes Mellitus; Diabetes, Gestational
• Other Study ID Numbers: MSH REB 09-0263-E