Diabetes - Medical Practice Guidelines

Gestational Diabetes

The onset of gestational diabetes occurs in women who manifest glucose intolerance during pregnancy. Since pregnancy stresses glucose metabolism, diabetes may manifest during this time.

Detection and Diagnosis

All pregnant women should be screened for glucose intolerance. Risk assessment for gestational diabetes should be undertaken at the first prenatal visit. Selective screening based on clinical factors or prior obstetrical history is inadequate.

Low Risk Characteristics

Women considered at minimal risk of having gestational diabetes requires no glucose testing. This category only applies to those women who meet all of the following characteristics:

• age < 25 years,
• weight normal before pregnancy,
• member of an ethnic group (generally white-non Hispanic) with a low prevalence of gestational diabetes,
• no known diabetes in first degree relatives,
• no history of abnormal glucose tolerance, and
• no history of poor obstetric outcome.

Women of average risk should have testing done at 24-28 weeks of gestation.

High Risk Characteristics

Women with clinical characteristics consistent with a high risk of gestational diabetes that include the following should have glucose testing as soon as feasible. If the initial screening is negative, they should be re-tested between 24-28 weeks of gestation.

• marked obesity,
• personal history of gestational diabetes,
  
• glycosuria, or
  
• a strong family history of diabetes.
  

Diagnosis of gestational diabetes is determined:

• by evaluating the results of the 100-g oral glucose tolerance during pregnancy that is interpreted according to the diagnostic criteria of O’Sullivan and Mahan Diagnostic Criteria:
  
  
• if two or more of the venous plasma glucose values are met or exceeded:
  

  – fasting: 95 mg/dl
  – 1 hour: 180 mg/dl
  – 2 hours: 155 mg/dl
  – 3 hours: 140 mg/dl
  

If either the fasting plasma glucose or random blood glucose meets or exceeds criteria for diagnosis, an oral glucose tolerance test (OGTT) is not needed.

Maternal Strategies

Close monitoring of the mother and fetus must be maintained for all women who are diagnosed as having gestational diabetes.

For the mother, close monitoring is needed to detect elevations of fasting or postprandial glucose in capillary blood or venous plasma and is designed to detect any deterioration of glucose homeostasis as the pregnancy proceeds.

Having the mother complete self-monitoring of capillary blood glucose is critical and allows her to participate in the diabetes management process.

Blood Glucose: 4 to 7 times per day (before and 2 hours after each meal and before the evening snack).

Urinary glucose monitoring of the mother is not adequate or appropriate.

Urine ketone testing must be done to ensure adequate caloric intake.

Fetal Strategies

It is necessary to increase the level of surveillance of the fetus in women diagnosed with gestational diabetes.
The degree of cumulative risk that the clinician feels the fetus is exposed to will determine the:

• starting time for increased monitoring,
• frequency, and
  
• techniques used to analyze fetal well-being.
  

Nutritional Counseling

All women diagnosed with gestational diabetes should receive nutritional counseling by a registered licensed dietitian. The nutrition plan should be individualized based on maternal weight and height.

The nutritional meal plan should include the provision of adequate calories and nutrients to address the needs during the prenatal period and must be consistent with the established maternal glucose goals.

Women without medical or obstetrical contraindications should be encouraged to start or continue a program of moderate exercise.

Insulin Therapy

Insulin therapy is initiated when dietary management does not consistently maintain the fasting plasma glucose.

• < 5.8 M (< 105 mg/dl), and/or
• the two-hour postprandial plasma glucose < 6.7 M (< 120 mg/dl) on two or more occasions within a one- to two-week interval.
  

Additional therapeutic strategies include the following:

• blood glucose self-monitoring is essential to meet therapeutic goals,
  
• during pregnancy, oral agents are contraindicated,
  
• moderate exercise may continue if the woman has had an active lifestyle,
  
• noncaloric sweeteners may be used in moderation, and
• women who have gestational diabetes should be encouraged to breastfeed.
  

Postpartum Follow-up Care

Women diagnosed with gestational diabetes should be followed after delivery to assess glucose intolerance. The initial evaluation should be completed six weeks after delivery and should include:

• a two-hour oral glucose tolerance test with a 75-g glucose load, unless either the fasting plasma glucose, or random blood glucose meets or exceeds criteria for diagnosis,
• a consultation with a registered dietitian, and
  
• discussion of contraception options - contraceptives with low doses of estrogen may be used safely in women with prior gestational diabetes whose postpartum glucose tolerance is normal.
  

Many women diagnosed with gestational diabetes will develop Type 2 diabetes. All women previously identified as having this disorder should continue to have follow-up evaluations at regular intervals during their entire lifetime. Stress the importance of weight control and to maintain BMI of less than 25.