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Home , Diabetes, Gestational diabetes

POSITION STATEMENT

Gestational Mellitus

AMERICAN DIABETES ASSOCIATION

DEFINITION, DETECTION, ● Member of an ethnic group with a low Mahan, modified by Carpenter and Cous- AND DIAGNOSIS prevalence of GDM tan, and are shown in Table 1. Alterna- ● No known diabetes in first-degree relatives tively, the diagnosis can be made using a Definition ● No history of abnormal tolerance 75-g glucose load and the glucose thresh- mellitus (GDM) is ● No history of poor obstetric outcome old values listed for fasting, 1 h, and 2 h defined as any degree of glucose intoler- (Table 2); however, this test is not as well ance with onset or first recognition during A fasting plasma glucose level Ͼ126 validated for detection of at-risk infants or (1). The definition applies mg/dl (7.0 mmol/l) or a casual plasma mothers as the 100-g OGTT. whether or only modification glucose Ͼ200 mg/dl (11.1 mmol/l) meets is used for treatment and whether or not the threshold for the diagnosis of diabe- OBSTETRIC AND PERINATAL the condition persists after pregnancy. It tes, if confirmed on a subsequent day, and CONSIDERATIONS — The pres- does not exclude the possibility that un- precludes the need for any glucose chal- ence of fasting (Ͼ105 recognized glucose intolerance may have lenge. In the absence of this degree of hy- mg/dl or Ͼ5.8 mmol/l) may be associated antedated or begun concomitantly with perglycemia, evaluation for GDM in women with an increase in the risk of intrauterine the pregnancy. with average or high-risk characteristics fetal during the last 4–8 weeks of Approximately 7% of all should follow one of two approaches: gestation. Although uncomplicated GDM are complicated by GDM, resulting in with less severe fasting hyperglycemia has more than 200,000 cases annually. The One-step approach: Perform a diagnos- not been associated with increased peri- prevalence may range from 1 to 14% of all tic oral (OGTT) natal mortality, GDM of any severity in- pregnancies, depending on the population without prior plasma or glucose creases the risk of fetal macrosomia. studied and the diagnostic tests employed. . The one-step approach may be Neonatal , , poly- cost-effective in high-risk patients or pop- cythemia, and may compli- Detection and diagnosis ulations (e.g., some Native-American cate GDM as well. GDM is associated with groups). Risk assessment for GDM should be un- an increased frequency of maternal hy- dertaken at the first prenatal visit. Women pertensive disorders and the need for ce- Two-step approach: Perform an initial sarean delivery. The latter with clinical characteristics consistent screening by measuring the plasma or se- with a high risk of GDM (marked , may result from fetal growth disorders rum glucose concentration 1 h after a and/or alterations in obstetric manage- personal history of GDM, , or a 50-g oral glucose load (glucose challenge strong family ) should ment due to the knowledge that the test [GCT]) and perform a diagnostic mother has GDM. undergo glucose testing (see below) as OGTT on that subset of women exceeding soon as feasible. If they are found not to the glucose threshold value on the GCT. have GDM at that initial screening, they Long-term considerations When the two-step approach is em- Women with GDM are at increased risk should be retested between 24 and 28 ployed, a glucose threshold value Ͼ140 weeks of gestation. Women of average for the development of diabetes, usually mg/dl (7.8 mmol/l) identifies approxi- type 2, after pregnancy. Obesity and other risk should have testing undertaken at mately 80% of women with GDM, and the 24–28 weeks of gestation. Low-risk sta- factors that promote ap- yield is further increased to 90% by using pear to enhance the risk of tus requires no glucose testing, but this a cutoff of Ͼ130 mg/dl (7.2 mmol/l). category is limited to those women meet- after GDM, while markers of islet cell– directed are associated ing all of the following characteristics: With either approach, the diagnosis with an increase in the risk of type 1 dia- of GDM is based on an OGTT. Diagnostic betes. Offspring of women with GDM are ● Age Ͻ25 years criteria for the 100-g OGTT are derived at increased risk of obesity, glucose intol- ● Weight normal before pregnancy from the original work of O’Sullivan and erance, and diabetes in late adolescence ●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●● and young adulthood. The recommendations in this paper are based on the evidence reviewed in the following publications: Report of the expert committee on the diagnosis and classification of diabetes mellitus. Diabetes Care 21 (Suppl. 1):S5–S19, 1998; and the Proceedings of the 4th International Workshop-Conference on Gestational Dia- THERAPEUTIC STRATEGIES betes Mellitus. Diabetes Care 21 (Suppl. 2):B1–B167, 1998. DURING PREGNANCY Originally approved 1986. Most recent review/revision, 2000. Abbreviations: GCT, glucose challenge test; GDM, gestational diabetes mellitus; IFG, ; IGT, impaired glucose tolerance; MNT, medical therapy; OGTT, oral glucose tolerance ● test; SMBG, self-monitoring of glucose. Maternal metabolic surveillance should © 2004 by the American Diabetes Association. be directed at detecting hyperglycemia

S88 DIABETES CARE, VOLUME 27, SUPPLEMENT 1, JANUARY 2004 Gestational Diabetes Mellitus

Table 1—Diagnosis of GDM with a 100-g Table 2—Diagnosis of GDM with a 75-g levels are used, insulin therapy is rec- oral glucose load oral glucose load ommended when MNT fails to main- tain self-monitored glucose at the mg/dl mmol/l mg/dl mmol/l following levels: Fasting plasma glucose Fasting 95 5.3 Fasting 95 5.3 Յ 1-h 180 10.0 1-h 180 10.0 105 mg/dl (5.8 mmol/l) 2-h 155 8.6 2-h 155 8.6 or 3-h 140 7.8 1-h postprandial plasma glucose Two or more of the venous plasma concentrations Յ Two or more of the venous plasma concentrations must be met or exceeded for a positive diagnosis. 155 mg/dl (8.6 mmol/l) must be met or exceeded for a positive diagnosis. The test should be done in the morning after an or The test should be done in the morning after an overnight fast of between 8 and 14 h and after at least 2-h postprandial plasma glucose Ն overnight fast of between 8 and 14 h and after at least 3 days of unrestricted diet ( 150 g Յ130 mg/dl (7.2 mmol/l) 3 days of unrestricted diet (Ն150 g carbohydrate per per day) and unlimited physical activity. The subject day) and unlimited physical activity. The subject should remain seated and should not smoke ● Measurement of the fetal abdominal should remain seated and should not smoke throughout the test. circumference early in the third trimes- throughout the test. ter can identify a large subset of infants pending on maternal weight and height with no excess risk of macrosomia in severe enough to increase risks to the is recommended. MNT should include the absence of maternal insulin ther- . Daily self-monitoring of blood the provision of adequate calories and apy. This approach has been tested pri- glucose (SMBG) appears to be superior nutrients to meet the needs of preg- marily in pregnancies with maternal to intermittent office monitoring of nancy and should be consistent with fasting serum glucose levels Ͻ105 plasma glucose. For women treated the maternal blood glucose goals that mg/dl (5.8 mmol/l). with insulin, limited evidence indicates have been established. Noncaloric ● Human insulin should be used when that postprandial monitoring is supe- sweeteners may be used in moderation. insulin is prescribed, and SMBG should rior to preprandial monitoring. How- ● For obese women (BMI Ͼ30 kg/m2), a guide the doses and timing of the insu- ever, the success of either approach 30–33% (to ϳ25 lin regimen. The use of insulin analogs depends on the glycemic targets that kcal/kg actual weight per day) has been has not been adequately tested in GDM. are set and achieved. shown to reduce hyperglycemia and ● Oral glucose-lowering agents have gen- ● glucose monitoring is not useful plasma triglycerides with no increase in erally not been recommended during in GDM. Urine monitoring may (2). Restriction of carbohy- pregnancy. However, one randomized, be useful in detecting insufficient ca- drates to 35–40% of calories has been unblinded clinical trial compared the loric or carbohydrate intake in women shown to decrease maternal glucose use of insulin and glyburide in women treated with calorie restriction. levels and improve maternal and fetal with GDM who were not able to meet ● Maternal surveillance should include outcomes (3). glycemic goals on MNT (4). Treatment and urine protein mon- ● Insulin is the pharmacologic therapy with either agent resulted in similar itoring to detect hypertensive disor- that has most consistently been shown perinatal outcomes. All patients were ders. to reduce fetal morbidities when added beyond the first trimester of pregnancy ● Increased surveillance for pregnancies to MNT. Selection of pregnancies for at the initiation of therapy. Glyburide is at risk for fetal demise is appropriate, insulin therapy can be based on mea- not FDA approved for the treatment of particularly when fasting glucose lev- sures of maternal glycemia with or GDM and further studies are needed in els exceed 105 mg/dl (5.8 mmol/l) or without assessment of fetal growth a larger patient population to establish pregnancy progresses past term. The characteristics. When maternal glucose its safety. initiation, frequency, and specific tech- niques used to assess fetal well-being will depend on the cumulative risk the Table 3—Criteria for the diagnosis of diabetes mellitus fetus bears from GDM and any other medical/obstetric conditions present. Normoglycemia IFG and IGT Diabetes mellitus* ● Assessment for asymmetric fetal growth by ultrasonography, particularly in FPG Ͻ100 mg/dl FPG Ն100 mg/dl and FPG Ն126 mg/dl early third trimester, may aid in identi- Ͻ126 mg/dl (IFG) fying that can benefit from ma- 2-h PG† Ͻ140 mg/dl 2-h PG† Ն140 mg/dl and 2-h PG† Ն200 mg/dl ternal insulin therapy (see below). Ͻ200 mg/dl (IGT) ——Symptoms of DM and casual Management plasma glucose ● All women with GDM should receive concentration Ն200 mg/dl nutritional counseling, by a registered DM, diabetes mellitus; FPG, fasting plasma glucose; 2-h PG, 2-h postload glucose. *In the absence of when possible, consistent with unequivocal hyperglycemia, a diagnosis of diabetes must be confirmed on a subsequent day by any one of the three methods included in the chart. In clinical settings, the FPG test is greatly preferred because of ease of the recommendations by the American administration, convenience, acceptability to patients, and lower cost. Fasting is defined as no calorie intake Diabetes Association. Individualization for at least 8 h. †This test requires the use of a glucose load containing the equivalent of 75 g anhydrous of medical nutrition therapy (MNT) de- glucose dissolved in water.

DIABETES CARE, VOLUME 27, SUPPLEMENT 1, JANUARY 2004 S89 Position Statement

● Programs of moderate physical Mellitus” (5). See Table 3 for diagnostic opment of obesity and/or abnormalities of have been shown to lower maternal criteria. If glucose levels are normal post- glucose tolerance. glucose concentrations in women with partum, reassessment of glycemia should GDM. Although the impact of exercise be undertaken at a minimum of 3-year on neonatal complications awaits rigor- intervals. Women with IFG or IGT in the References ous clinical trials, the beneficial glucose- should be tested for 1. Metzger BE, Coustan DR (Eds.): Proceed- ings of the Fourth International Work- lowering effects warrant a recommen- diabetes annually; these patients should shop-Conference on Gestational Diabetes dation that women without medical or receive intensive MNT and should be Mellitus. Diabetes Care 21 (Suppl. 2):B1– obstetrical contraindications be en- placed on an individualized exercise pro- B167, 1998 couraged to start or continue a program gram because of their very high risk for 2. Franz MJ, Bantle JP, Beebe CA, Brunzell JD, of moderate exercise as a part of treat- development of diabetes. All patients with Chiasson J-L, Garg A. Holzmeister LA, ment for GDM. prior GDM should be educated regarding Hoogwerf B, Mayer-Davis E, Mooradian ● GDM is not of itself an indication for lifestyle modifications that lessen insulin AD, Purnell JQ, Wheeler M: Evidence- cesarean delivery or for delivery before resistance, including maintenance of nor- based nutrition principles and recommen- 38 completed weeks of gestation. Pro- mal body weight through MNT and phys- dations for the treatment and prevention of longation of gestation past 38 weeks in- ical activity. that worsen diabetes and related complications (Tech- nical Review). Diabetes Care 25:148–198, creases the risk of fetal macrosomia insulin resistance (e.g., , 2002 without reducing cesarean rates, so that nicotinic acid) should be avoided if pos- 3. Major CA, Henry MJ, De Veciana M, Mor- delivery during the 38th week is recom- sible. Patients should be advised to seek gan MA: The effects of carbohydrate re- mended unless obstetric considerations medical attention if they develop symp- striction in patients with diet-controlled dictate otherwise. toms suggestive of hyperglycemia. Educa- gestational diabetes. Obstet Gynecol 91: ● Breast-feeding, as always, should be en- tion should also include the need for 600–604, 1998 couraged in women with GDM. to ensure optimal glyce- 4. Langer L, Conway DL, Berkus MD, Xenakis mic regulation from the start of any sub- EM-J, Gonzales O: A comparison of gly- LONG-TERM THERAPEUTIC sequent pregnancy. Low-dose estrogen- buride and insulin in women with gesta- CONSIDERATIONS — Reclassifica- oral contraceptives may be tional diabetes mellitus. N Engl J Med 343: 1134–1138, 2000 tion of maternal glycemic status should be used in women with prior histories of 5. Expert Committee on the Diagnosis and performed at least 6 weeks after delivery GDM, as long as no medical contraindi- Classification of Diabetes Mellitus: Report and according to the guidelines of the cations exist. of the Expert Committee on the Diagnosis “Report of the Expert Committee on the Offspring of women with GDM and Classification of Diabetes Mellitus. Diagnosis and Classification of Diabetes should be followed closely for the devel- Diabetes Care 20:1183–1197, 1997

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