Gestational Diabetes Update

Leigh Caplan RN CDE

Marsha Feldt RD CDE

SUNDEC - Diabetes Education Centre

May 22, 2009

Learning Objectives

• Review physiology of pregnancy and gestational diabetes

• Review CDA clinical practice guidelines for diagnosis and management of gestational diabetes

• Highlight nutrition therapy approaches• Discuss role of hospital based gestational diabetes

programs• Discuss post partum considerations for diabetes

risk and prevention

Case study:

Sue comes to see you for nutrition counselling

• 32 years old, BMI 25• family history of type 2• G1P0 26 wks gestation• Informs you she just received the diagnosis of

gestational diabetes• GTT results - 5.1, 10.7, 9.1

What do you do?

• Definition: Hyperglycemia with onset or first recognition during Pregnancy

• Prevalence 3.7% in non-aboriginal 8-18% in aboriginal populations

CDA CPG 2008

Gestational Diabetes

Physiology in Late Pregnancy

• Characterized by accelerated growth of the fetus

• A rise in blood levels of several diabetogenic hormones

• Food ingestion results in higher and more prolonged plasma glucose concentration

Physiology in Late Pregnancy

• Maternal insulin and glucagon do not cross the placenta

• During late pregnancy a women’s basal insulin levels are higher than non-gravid levels

• Food ingestion results in a twofold to threefold increase in insulin secretion

(Franz, M.J., 2001)

Physiology of GDM

• Gestational hormones

induce insulin

resistance

• Inadequate insulin

reserve and

hyperglycemia ensues

Fetal Risks

• Macrosomia - shoulder dystocia and related complications • Jaundice• Hypoglycemia• No increase in congenital anomalies

Exposure to GDM in utero

• LGA children or those born to obese mother have a 7% risk of developing IGT at 7-11 yrs age

• Breastfeeding may lower risk CDA CPG 2008

Gestational Diabetes

Maternal Risks

• C-section

• Pre-eclampsia

• Recurrence risk of GDM is 30-50%

• 30-60% lifetime risk in developing IFG, IGT or type 2 diabetes

CDA CPG 2008

Gestational Diabetes

GDM Screening

• All women should be screened for GDM between 24-28 weeks– vs. risk factor based approach which can

miss up to ½ the cases of GDM

• Women with multiple risk factors should be screened in the first trimester

Risk Factors: for first trimester screening

• > 35 yrs• BMI > 30 • Previous diagnosis of GDM• Delivery of a mascrosomic baby• Member of a high-risk population

– (Aboriginal, Hispanic, South Asian, Asian, African)• Acanthosis nigricans• Corticosteroid use• PCOS

Diagnosis of Gestational Diabetes

Gestational Diabetes Screen (GDS)

1 hr after 50g load of glucose

Value 75 g OGTT indicated

<7.8 mmol/L no

7.8-10.2 mmol/L yes

> 10.3 mmol/L No - GDM

Diagnosis of Gestational Diabetes

75 g OGTT

• GDM = 2 or more values greater than or equal to

• IGT = single abnormal value

Fasting > 5.3 mmol/L

1 hr > 10.6 mmol/L

2 hr > 8.9 mmol/L

Management of Gestational Diabetes

• Strive to achieve glycemic targets• Receive nutrition counselling from an

Registered Dietitian• Encourage physical activity • Avoid ketosis• If BG targets are not reached within 2

weeks then insulin therapy should be started

Target Blood Glucose Values for GDM

• Fasting/Pre-prandial: 3.8 – 5.2 mmol/L

• 1 hour 5.5 - 7.7mmol/L

• 2 hour 5.0 - 6.6mmol/L

Nutrition Therapy as treatment for GDM

• A tool to achieve appropriate nutrition and glycemic goals of pregnancy

• to normalize fetal growth and birth weight

Medical Nutrition Therapy for GDM

Definition:

A carbohydrate controlled meal plan with adequate nutrition for appropriate weight gain, normoglycemia, and the absence of ketones

Clinical Outcomes

• Achieve and maintain normoglycemia

• Promote adequate calories for wt gain in absence of ketones

• Consume food providing adequate nutrients for maternal and fetal health

GDM Nutrition Controversies

• What is a healthy weight gain for an obese woman with GDM?

• How far to manipulate energy intake?

• Does the balance of carbohydrate and fat matter?

Excess Weight Gain

• May increase incidence of GDM in future pregnancy

Obese women have larger babies• More likely to develop macrosomia if

gain >25lb• More likely to develop macrosomia with

high post prandial BG levels

Calorie Restricted Diets

• Avoid severe restriction - <1500 kcal not recommended

• Avoid ketones • 33% calorie restriction slowed wt gain

and improved BG – 1800 kcal

Role of Carbohydrate

• Carbohydrate can be modified to control postprandial glucose elevations

• High fiber not associated with lower glucose levels in GDM

• Lower carb intake (<42%) associated with; less insulin; less LGA

• Postprandial correlated with %CHO at meal; breakfast less tolerance

Emphasis for GDM

• Healthy Eating following CFG appropriate for adequate weight gain

• DRI= minimum 175 g CHO/day• Spacing of CHO into 3 meals & 2 to 4 snacks

• Smaller amounts of CHO at breakfast*

• Evening snack is important to prevent ketosis overnight

• Encourage activity as tolerated

Carbohydrate Counting with “Beyond the Basics”

• Canadian Diabetes Association meal planning guide

• Based on Canada’s food guide groups

• Each food group outlines portion sizes of various foods

• Each carbohydrate choice (grains/starch, fruit, milk) = 15 grams carbohydrate

Grains – 8-10 choices Fruit – 2-3 choices Milk – 3-4 choices

Dietary Fat in GDM

• up to 40% of total energy intake during pregnancy

• choose food source which are lower in saturated and transfats

Artificial Sweeteners

When used within ADI– Aspartame – does not cross placenta; no adverse

effects– Sucralose (splenda) – acceptable– Acesulfame potassium – acceptable

• Saccharin – crosses placenta; not acceptable• Cyclamates – not acceptable

Back to Sue 3 weeks later

• Trying to work with meal plan• Weight has been stable for 3 weeks• Blood glucose readings:

– Fasting 5.0 to 5.7– 2 hours pc breakfast 4.6 to 5.3– 2 hours pc lunch 5.7 to 6.5– 2 hours pc dinner 7.2 to 7.9What do you discuss with Sue?

Purpose of Insulin

• To achieve plasma glucose control nearly identical to those observed in women without diabetes

• Must be individualized • Insulin requirements will

change with various

stages of gestation(ADA. Medical Management of Pregnancy

Complicated by Diabetes., 2000)

Types of Insulin

Approved in pregnancy• Fast acting: Humalog , NovoRapid• Short acting: Regular/R• Intermediate acting: NPH/N

– Detemir can be used if woman unable to tolerate NPH ( Ongoing study to evaluate use in pregnancy)

– Glargine – avoid use

Devices for Insulin Delivery

Considerations for Adjusting Insulin

• Look for patterns in blood glucose readings

• Adjust for hypoglycemia first

• Then adjust for high blood glucose

Can oral hypoglycemia agents be used to treat GDM?

• Glyburide– Does not cross the placenta– Controlled BG in 80% of women– Women with high FBG less likely to respond to

Glyburide– More adverse perinatal outcomes compared to

insulin• Not approved in Canada

– use is considered off-label and requires appropriate discussions of risks with patient

CDA CPG 2008

Metformin – alone or with insulin was not associated with

increased perinatal complications compared with insulin

– Less severe hypoglycemia in neonates– Does cross the placenta – long term study MiG

TOFU ongoing

• Not approved in Canada– use is considered off-label and requires

appropriate discussions of risks with patientNEJM, 2008

Postpartum Physiology:

Once the placenta is delivered:

• Hormones clear from circulation

• They will be monitored in hospital if blood glucose remains elevated may require medications

Postpartum Focus:

• Encourage follow up with health care provider to have – OGTT (6 weeks to 6 months 75 g OGTT)– weight management, – postpartum visit with a registered dietitian– Encourage breastfeeding– Monitoring occasionally with meter– Future pregnancy

Breastfeeding and DM meds

• Both metformin and glyburide/glipizide are found at low concentrations (or not at all) in breast milk– Hale et al, Diabetologia 2002– Feig et al, Diabetes Care 2005– Can be considered however, more long-

term studies needed

SUNDEC– Diabetes Education Centre

(416) 480-4805

• Multidisciplinary team of health professionals ( RN, RD)

• Self referral• Individual counselling• Group education classes

• Type 2, Pre-diabetes, Diabetes Prevention and Seniors programs

Case 2Justine

Justine was diagnosed with gestational diabetes at 20 weeks, – pre-preg BMI = 28.7, GTT results were: 6.2, 10.2, 9.8

She is now at 25 weeks • FBS 6.1 – 7.4• 3 meals and 1 -2 snacks.

– Diet history: Oatmeal at breakfast, lunch and dinner consist of aprox. ½ cup rice, lots of vegetables and meat, in the afternoon a piece of fruit, 2 cups of milk at bed

• What would you do?

www.diabetes.ca

Resources and References

Canadian Diabetes Association: www.diabetes.ca-Recommendations for Nutrition Best Practice in the

Management of GDM-2003 Canadian Diabetes Association Clinical Practice

Guidelines for the Prevention and Management of Diabetes in Canada

Nutrition for a Healthy Pregnancy: National Guidelines for the Child Bearing Years

Healthy Eating is in Store for you:www.healthyeatingisinstore.ca