Twenty studies were evaluated to investigate the relationship between impaired glucose tolerance (definitions vary) during pregnancy and poor outcomes.  Two studies demonstrate the metabolic similarities between impaired glucose tolerance and gestational diabetes mellitus.  Twelve studies report increased risks of large for gestational age newborns and macrosomia in women with impaired glucose tolerance.  Additional research notes increased risks of preterm birth, perinatal morbidity and neonatal hypoglycemia.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Fourteen studies were evaluated to investigate the relationship between physical activity during pregnancy and maternal/neonatal outcomes and glycemic control in women with gestational diabetes mellitus.  Regular physical activity during pregnancy reduces the risk of gestational diabetes mellitus, as well as the common discomforts of pregnancy, without a negative effect on maternal or neonatal outcomes.  Physical activity for 30 minutes per day for a minimum of three times per week is needed to aid with improved glycemic control.  In addition, social support may encourage women with gestational diabetes mellitus to engage in physical activity.

 

 

 

 

 

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Ten studies were evaluated to investigate the consumption of macronutrients in pregnant women and women with gestational diabetes mellitus.  Carbohydrate intake affects postprandial blood glucose levels; Increased postprandial blood glucose levels are associated with increased incidence of large-for-gestational age infants and increased rate of Cesarean sections.  Three studies showed improved outcomes at carbohydrate intakes of less than 45% of energy .  Research is limited regarding protein, fat, fiber and glycemic index in women with gestational diabetes mellitus; further research is needed in these areas.   

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Twelve studies were evaluated to investigate nutrition and physical activity interventions and the prevention of gestational diabetes.  Obesity, excessive weight gain prior to pregnancy and increased saturated fat intake are associated with the development of glucose abnormalities in pregnancy and increased risk of gestational diabetes.  Evidence regarding the consumption of micronutrients are conflicting, as the relationship between the prevalence of gestational diabetes and vitamin and mineral intake may be related to nutritional adequacy of the diet and gestational weight gain; further research is needed in this area.   

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Twenty-four studies were evaluated to investigate the use of pharmacological therapy for women with gestational diabetes mellitus (GDM). In conjunction with nutrition therapy, pharmacological therapy is indicated in women with gestational diabetes mellitus when optimal blood glucose levels have not been maintained and/or when the rate of fetal growth is excessive. 

Insulin therapy has been shown to be safe and effective in maintaining optimal blood glucose levels and reducing incidence of macrosomia, fetal morbidity and mortality. Five studies regarding the use of insulin analogs reported that lispro or aspart as rapid acting insulins may improve glycemic control and reduce the incidence of macrosomia in neonates. Research on glargine is limited. 

Eight studies reported that glyburide therapy is effective in maintaining glycemic control in conjunction with nutrition therapy, especially in women with less severe disease. Research on metformin is limited.  Further research on other antidiabetes agents in women with gestational diabetes mellitus is needed.   

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

A matched population study and two reviews were evaluated to investigate breastfeeding in women with gestational diabetes mellitus (GDM).  Short duration of breastfeeding results in long-term improvements in glucose metabolism even after adjustment for maternal age, BMI, and use of insulin during pregnancy. Breastfeeding may also reduce the risk of type 2 diabetes in children.   Further research is needed regarding breastfeeding in women with gestational diabetes mellitus.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Sixteen studies were evaluated regarding blood glucose monitoring and ketone testing in pregnant women and in women with gestational diabetes mellitus.   Six studies report that fasting blood glucose monitoring results in improved glucose control and therefore less risk of poor maternal and neonatal outcomes.   Seven studies report a correlation between postprandial blood glucose values with improved maternal and neonatal outcomes; however, ideal postprandial testing timing is unknown.  Two of three studies regarding ketonemia and ketonuria with poor metabolic control during a diabetic pregnancy report a positive association with lower IQ in offspring.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

While there are recognizable benefits of the use of nonnutritive sweeteners with the maintenance of blood glucose control, to date[2008] there is limited evidence to support the use or nonuse of nonnutritive sweetners (NNS) in pregnancy, and even less evidence addressing this issue specifically in gestational diabetes mellitus (GDM).   The FDA has approved aspartame, acesulfame potassium, sucralose, saccharin and neotame for general use, while stevia has not been approved.  The use of FDA-approved nonnutritive sweeteners during pregnancy is acceptable with the exception of aspartame for pregnant women with hyperphenylalanine in the blood and phenylketonuria.  The American Medical Association suggests avoiding saccharin during pregnancy due to possible slow fetal clearance.  

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Five studies were evaluated to investigate the relationship between nutrition interventions and the recurrence of gestational diabetes mellitus in women with a history of Gestational Diabetes Mellitus (GDM).  In three studies reporting recurrence of GDM, prevalence ranged from 30% to 65%.  Five studies evaluating modifiable risk factors for GDM recurrence include higher prepregnancy body mass index and weight gain between pregnancies. 

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Two studies were evaluated to investigate caloric intake and appropriate weight gain. Research on caloric requirements is limited: Further research is needed on the determination of caloric requirements in women with gestational diabetes mellitus.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Six studies were evaluated to investigate the relationship between Medical Nutrition Therapy on pregnancy outcomes in women with gestational diabetes mellitus.  Medical Nutrition Therapy, initiated within one week of diagnosis and with a minimum of three nutrition visits, results in decreased hospital admissions and insulin use, improves likelihood of normal fetal and placental growth, and reduces risk of perinatal complications, especially when diagnosed and treated early.

 

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Seven studies were evaluated to investigate the relationship between nutrition interventions and the diagnosis of type 2 diabetes in women with a history of gestational diabetes.  In four studies reporting development of type 2 diabetes, ranging from two to fifteen years in length, prevalence ranged from 15% to 40%.  All seven studies examining the association between history of GDM and type 2 diabetes mellitus reported that the risks of developing diabetes can be reduced with weight loss.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.