Gestational Diabetes Mellitus Revisited

Gestational Diabetes Mellitus Revisited 

Today is world diabetes day. The International Diabetes Federation has released new data in support of its campaign against Diabetes quoting that “1 in 7 births is affected by gestational diabetes” and “One quarter of all births are affected by high blood glucose during pregnancy in South-East Asia.”

 This article is based on The International Federation of Gynecology and Obstetrics (FIGO) Initiative on gestational diabetes mellitus: A pragmatic guide for diagnosis, management, and care.

• The International Diabetes Federation (IDF) estimates that one in six live births (16.8%) are to women with some form of hyperglycemia in pregnancy.

• While 16% of these cases may be due to diabetes in pregnancy (either preexisting diabetes—type 1 or type 2—which antedates pregnancy or is first identified during testing in the index pregnancy), the majority (84%) is due to gestational diabetes mellitus (GDM).

• The definition of GDM is still evolving.

• Hyperglycemia first detected at any time during pregnancy should be classified either as diabetes mellitus in pregnancy (DIP) or GDM.

• When the level of hyperglycemia first detected by testing at any time during the course of pregnancy meets the criteria for diagnosis of diabetes in the nonpregnant state, the condition is called DIP. Those criteria are:

      1) Fasting plasma glucose ≥7.0 mmol/L (126 mg/dL); and/or

      2) 2-hour plasma glucose ≥11.1 mmol/L (200 mg/dL) following a 75-g oral glucose load; or

      3)Random plasma glucose ≥11.1 mmol/L (200 mg/dL) in the presence of diabetes   symptoms.

• DIP may either have been pre-existing diabetes (type 1 or type 2) antedating pregnancy, or diabetes first diagnosed during pregnanc.

• When hyperglycemia detected during routine testing in pregnancy (generally between 24 and 28 weeks) does not meet the criteria of DIP it is called GDM.

            To address the global burden of GDM, FIGO recommendations:

• Universal testing-- All pregnant women should be tested for hyperglycemia during pregnancy using a one-step procedure and FIGO encourages all countries and its member associations to adapt and promote strategies to ensure this.

• As per the recommendation of the IADPSG (2010) and WHO (2013), the diagnosis of GDM is made using a single-step 75-g OGTT when one or more of the following results are recorded during routine testing specifically between weeks 24 and 28 of pregnancy or at any other time during the course of pregnancy:

     1)Fasting plasma glucose 5.1−6.9 mmol/L (92−125 mg/dL);

     2)1-hour post 75-g oral glucose load ≥10 mmol/L (180 mg/dL);

     3)2-hour post 75-g oral glucose load 8.5–11.0 mmol/L(153−199 mg/dL)

• Asian Indians are considered to be at the highest risk of gestational diabetes. Based on studies from India and keeping in mind the already high burden and rising prevalence of diabetes and the realities of resource constraints within the health system in India, as well as the high rate of deliveries (27 million each year), the Diabetes in Pregnancy Study Group in India (DIPSI) developed the following guideline for diagnosis of GDM in the community. This guideline has been endorsed by the Ministry of Health, Government of India, the Federation of Obstetrics and Gynecological Societies of India (FOGSI), and the Association of Physicians of India (API)
• For Asian Indians Testing for GDM is recommended twice during prenatal care. The first testing should be done during first prenatal contact as early as possible in pregnancy. The second testing should be done ideally during 24−28 weeks of pregnancy if the first test is negative. If women present beyond 28 weeks of pregnancy, only one test is to be done at the first point of contact.

• The management of GDM should be in accordance with available national resources and infrastructure even if the specific diagnostic and treatment protocols are not supported by high-quality evidence, as this is preferable to no care at all.

• Life style modification is the corner stone in management of DIP and GDM.

• Nutritional therapy includes an individualized food plan to optimize glycemic control. Medical nutritional therapy in pregnancy can be described as “a carbohydrate-controlled meal plan that promotes adequate nutrition with appropriate weight gain, normoglycemia, and the absence of ketosis.

• Daily energy intake of approximately 2050 calories (minimum of 175 g carbohydrates/day) in all BMI categories in women with GDM was reported to reduce weight gain, maintain euglycemia, avoid ketonuria, and achieve average birth weights of 3542 g.

• Oral antidiabetic agents  Insulin, glyburide, and metformin are safe and effective therapies for GDM  during the second and third trimesters, and may be initiated as first-line treatment after failing to achieve glucose control with lifestyle modification. Among OADs, metformin may be a better choice than glyburide.

• Insulin should be considered as the first-line treatment in women with GDM who  are at high risk of failing on OAD therapy, including some of the following factors

       • Diagnosis of diabetes <20 weeks of gestation

             • Need for pharmacologic therapy >30 weeks

       • Fasting plasma glucose levels >110 mg/dL

       • 1-hour postprandial glucose >140 mg/dL

       • Pregnancy weight gain >12 kg

• The postpartum period is crucial, not only in terms of addressing the immediate perinatal problems, but also in the long term for establishing the basis for early preventive health for both mother and child, who are at a heightened risk for future obesity, metabolic syndrome, diabetes, hypertension, and cardiovascular disorders.

• Progression to diabetes is more common in women with a history of GDM compared with those without a GDM history. 
• Both “intensive lifestyle” and metformin have been shown to be highly effective in delaying or preventing diabetes in women with IGT and a history of GDM.

• The current EBCOG proposal is to screen women with a history of GDM at 6−12 weeks postpartum using the 2-hour 75-g OGTT with nonpregnancy diagnostic criteria. Women with a history of GDM should have lifelong screening for the development of diabetes or prediabetes at least every 3 years.

     References:

• http://www.ijgo.org/article/S0020-7292%2815%2930033-3/pdf

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