Gestational diabetes mellitus.

Continuing education and the APD program

This quiz is an ideal activity for APD members to include in your CPD log, where it relates to personal learning goals. Record the time taken, to the nearest hour, to complete the quiz and any associated research.

This quiz has been prepared by Lynda Gillen, BNut.Diet(Hons), APD, at the Smart Foods Centre, University of Wollongong. Correspondence should be directed to Lynda Gillen, Smart Foods Centre, University of Wollongong NSW 2522

Gestational Diabetes Mellitus (GDM) identifies women with demonstrated glucose intolerance. Due to a continuum of perinatal risk related to rising maternal blood glucose levels, nutrition therapy is based on maintaining glycaemic control. However, this is not the end of the story and an understanding of future risks and appropriate primary prevention strategies will enable more comprehensive dietary management of these women. This continuing education quiz focuses on the key aspects in the management of women with gestational diabetes for dietitians working in the area.

1. Which of the following correctly defines Gestational Diabetes Mellitus (GDM)?

a. onset or first recognition of impaired insulin sensitivity of variable severity during the current pregnancy

b. any degree of impaired insulin secretion with onset or first recognition during the current pregnancy

c. any degree of glucose intolerance with onset or first recognition during the current pregnancy

d. impaired glucose tolerance observed during pregnancy

2. Which of the following does not represent an identifiable risk factor for GDM?

a. older

b. shorter

c. taller

d. overweight

3. Which pregnant women should be screened for GDM?

a. those with one or more identifiable risk factors

b. those with two or more identifiable risk factors

c. those with symptoms recognised as those associated with GDM

d. all pregnant women should be screened for GDM

4. Of what are women with GDM at increased risk?

a. macrosomia, premature delivery and caesarian section

b. developing GDM in subsequent pregnancies and type 2 diabetes later in life

c. developing macro- and micro-vascular disease and associated complications

d. a and b only

e. all of the above

5. Which best describes the current goals of medical nutrition therapy (MNT) for GDM?

a. appropriate weight gain, normoglycemia and absence of ketones 

b. appropriate weight loss, normoglycemia and absence of ketones

c. appropriate weight gain, normoglycemia and reduction in ketones

d. appropriate weight loss, normoglycemia and reduction in ketones

6. To reduce the risk of subsequent diabetes and related complications in women with GDM, primary prevention strategies are required. Which of the following is not an appropriate primary prevention strategy?

a. reducing weight or preventing weight gain after pregnancy

b. increasing physical activity after pregnancy

c. promoting food choices and eating patterns that facilitate weight management and address blood lipid profile

d. continuing home blood glucose monitoring after pregnancy

e. regular screening for impaired glucose tolerance after pregnancy

7. Which evidence demonstrates that the following is/are necessary to produce long-term weight loss?

a. structured, intensive lifestyle programs

b. participant education

c. individualised counselling

d. frequent participant contact

e. all of the above

8. What are the goals for dietary fat intake for the prevention and management of diabetes?

a. the same as for the general population

b. less than 30% of energy from total fat

c. less than 10% of energy derived from saturated fats (< 7% of energy for persons with elevated LDL-cholesterol), and approximately 10% of energy from polyunsaturated fat (PUFA)

d. a and c

9. Which are appropriate fat-rich food choices for achievement of fatty acid goals?

a. low fat dairy products and lean/trim meat choices

b. low fat products from all dietary sources

c. regular intakes of oily fish, walnuts, soy and omega-3-enriched products

d. a and c only

Answers

1. c.

This definition applies whether 'insulin' or 'diet only' modification is required for treatment and whether or not the condition persists after pregnancy (1). It does not exclude the possibility that unrecognised impaired glucose tolerance may have existed prior to the current pregnancy. Women with this condition have shown signs of varying degrees of either insulin sensitivity or impairment of insulin secretion, or both. Either way, the diagnosis of GDM is based on an oral glucose tolerance test (OGTT) undertaken during the current pregnancy.

2. c.

Those at increased risk of GDM tend to be older (> 24 years), shorter, overweight or obese, multiparous, members of specific ethnic origins, have first-degree relatives with diabetes, have a history of previous GDM and/or other abnormal glucose tolerance, and/or history of poor obstetric outcomes (2). However, women with no observable risk factors can also develop GDM.

3. d.

Recommending organisations, The Australasian Diabetes in Pregnancy Society (ADIPS) (3) and American Diabetes Association (ADA) (1), recommend either universal screening or average-risk screening, respectively, over high-risk screening of pregnant women for GDM. This is because of the important implications for the health of both the baby and the mother, and because women with low-risk are limited to those meeting all low risk characteristics for age (< 25 years), weight, ethnicity, histories of diabetes, abnormal glucose tolerance and poor obstetric outcomes.

4. e.

In the short term, women diagnosed with GDM are at increased risk of macrosomia or a large-for-gestational age baby, and adverse pregnancy outcomes, including premature delivery and/or special care of the newborn, caesarian section, and other delivery interventions (2). In the future, these women are at increased risk of developing GDM in subsequent pregnancies and of type 2 diabetes later in life. The newborn is also at increased risk of diabetes. Diabetes is a clinical feature of the Metabolic Syndrome which associates obesity, hypertension and hyperlipidaemia with insulin resistance and glucose intolerance. Those at risk of one are at increased risk of other aspects of the Metabolic Syndrome including cardiovascular disease, coronary heart disease and stroke, and long-term micro-vascular complications such as retinopathy (blindness), neuropathy and renal failure (dialysis/transplantation), foot ulcers and lower limb amputation.

5. a.

ADA recommends appropriate weight gain for pregnancy and moderate carbohydrate restriction for the achievement and maintenance of normoglycemia (4). In overweight and obese women with GDM, moderate energy restriction may also be appropriate. However, hypocaloric diets may result in ketonemia with resultant increases in free fatty acids and ketonuria. Therefore, energy levels should be adequate to meet both maternal and fetal health needs as well as avoid ketonemia. A modest energy restriction (30% calorie-restriction of estimated energy needs) appears to reduce mean blood glucose levels without elevation in plasma free fatty acids or ketonuria.

6. d.

Continued home blood glucose monitoring after the pregnancy is unnecessary and burdensome on the individual. Large multicentre trials targetting lifestyle modifications aimed at reducing or preventing weight gain and increasing physical activity have demonstrated a reduction in the development of diabetes and related complications in high risk individuals (2). Women with GDM are also more likely to develop cardiovascular disease than other women, cancelling any hormonal advantage over men (2). Food choices and eating patterns aimed at achieving energy balance and an optimal lipid profile reduces the risk of heart disease (4). Hence, OGTT screening conducted six weeks after delivery and at a minimum of three-year intervals and lifestyle changes combine to provide important primary prevention objectives for these women (1).

7. e.

Evidence from lifestyle intervention trials demonstrates that structured, intensive lifestyle programs involving participant education, individualised counselling, reduced dietary fat (total and saturated) and energy intake, regular physical activity and frequent participant contact are necessary to produce long-term weight loss of as much as five to seven percent of starting weight. Exercise by itself has only a modest effect on weight loss (4). Weight loss with behavioural therapy alone also has been modest. Behavioural approaches may be most useful as an adjunct to other weight loss strategies. Exercise, however, is to be encouraged because it improves/lowers blood glucose and is important in the long-term maintenance of weight loss. The medical literature documents that without the other components of an intensive lifestyle program, the long-term outcomes of weight loss due to caloric restriction alone are poor. The majority regain the weight they have lost.

8. d.

Studies in persons with diabetes demonstrating effects of specific percentage intakes of dietary saturated fat and polyunsaturated fat and specific amounts of dietary cholesterol are limited (4). Therefore, the goal for persons with and at risk of diabetes is the same as for the general population. According to ADA recommendations A-Level evidence supports less than 10% of energy intake to be derived from saturated fat (less than 7% of energy for persons with elevated LDL-cholesterol). When weight loss is not a goal this reduction can be replaced by either carbohydrate or monounsaturated fat (B-level evidence). No limit is given for total fat intake in acknowledgement of the need for individualised advice based on lipid profile, weight management goals and food preferences, as well as evidence that energy balance is more dependent on the total amount of calories in the diet. Compared to saturated fat, polyunsaturated fats appear to lower plasma total- and LDL-cholesterol, and omega-3 polyunsaturated fatty acids have cardio-protective effects (C-Level evidence).

9. d.

National nutrition surveys in Australia and the US have demonstrated that the general population consumes too much saturated fat and too little polyunsaturated fat compared with current recommendations (5). Advice for the achievement of an improved lipid profile therefore requires apposing strategies, i.e. a reduction in saturated fat intake (using low fat and trim meat and dairy choices), and an increase in polyunsaturated fat intake (including regular intakes of oily fish such as salmon and tuna, walnuts, soy and omega-3-enriched products). The American Diabetes Association recommends two to three servings of fish per week as a dietary source of omega-3 polyunsaturated fat (B-level evidence) (4).

References

1. American Diabetes Association. Gestational Diabetes Mellitus. Position Statement. Diabetes Care 2003;26Suppl1:103S-5S.

2. National Evidence Based Guidelines for the Management of Type 2 Diabetes Mellitus. Prepared by the Australian Centre for Diabetes Strategies, Prince of Wales Hospital, Sydney, for the Diabetes Australia Guideline Development Consortium. www.health.gov.au/pq/diabetes/ebguide.htm.nhmrc.gov.au/publications/synopses/cp86syn.htm. Accessed 18 August 2004.

3. Hoffman L, Nolan C, Wilson D, Oats JJN, Simmons D. Gestational diabetes mellitus--management guidelines [Consensus statement]. Med J Aust 1998;169:93-7; and ADA, 2003.

4. American Diabetes Association Nutrition Principles and Recommendations in Diabetes. Diabetes Care 2004;27:36S-46S.

5. Cook T, Rutishauser I, Allsopp R. The Bridging Study--comparing results from the 1983, 1985 and 1995 Australian national nutrition surveys. 2001: The Australian Food and Nutrition Monitoring Unit: University of Queensland, Brisbane. www.sph.uq.edu/nutition/monitoring/index.ht. Accessed 18 August 2004.