ACOG practice bulletin: gestational diabetes mellitus

Question 0

What are maternal complications of GDM?

What is the long-term risk of progression to diabetes mellitus?

Answer 0

Gestational hypertension, preeclampsia, cesarean section

50% with GDM developed diabetes 22-28 years after pregnancy
60% of Latin American women with GDM develop diabetes by five years

Question 1

Define GDM.

What is the rate during pregnancy?

What ethnicities are at increased risk?

Answer 1

Carbohydrate intolerance with onset or recognition during pregnancy

6-7%

Hispanic, African-American, Native American, Asian, Pacific Islander

Question 2

What are the fetal complications associated with GDM?

Answer 2

Macrosomia, neonatal hypoglycemia, hyperbilirubinemia, operative delivery, shoulder dystocia, birth trauma

Question 3

How is screening for GDM routinely performed in the US?

What percentage of patients with GDM would be missed if historic factors were used to screen alone?

What percentage of low risk women would not require screening?

Answer 3

50 g one hour glucose tolerance test

50%

10%

Question 4

What are the indications for early screening for GDM?

Answer 4

Previous history of GDM
Known impaired glucose metabolism
Obesity with BMI greater than or equal to 30

Question 5

When is routine screening recommended?

Answer 5

24-28 weeks

Question 6

What testing is performed if screening is failed?

Answer 6

100 g, three-hour diagnostic oral glucose tolerance test

Question 7

Comment on the recommended 75 g, two hour GTT for screening and diagnosis.

Answer 7

Recommended by the International Association of Diabetes and Pregnancy Study Group in 2010, however this would increase prevalence to 18% without evidence of improved outcomes. Not recommended by ACOG.

Question 8

What screening threshold is used in our practice?

Answer 8

140 mg/dL

The thought is that this higher threshold might identify women at greater risk of adverse outcomes and result in lower false positive screening results

Question 9

What diagnostic thresholds are used for the 3-hour glucose tolerance test in our practice?

Comment on this choice.

Answer 9

Carpender and Coustan
95/180/155/140 mg/dL

This threshold increases the diagnosis of GDM by 50% over the National Diabetes Group data.

Question 10

How is blood glucose monitoring recommended in our practice?

What is the goal?

Answer 10

Four times daily with fasting and one hour postprandial

Goal less than 95 for fasting and 130 for postprandial; ACOG recommends less than 140 for one hour postprandial values.

Question 11

Why is one hour postprandial measurement recommended?

Answer 11

Better glycemic control, lower incidence of LGA infants, lower rates of cesarean section due to CPD

Question 12

What treatment is recommended for all women with GDM?

Answer 12

Nutritional counseling

Moderate exercise program, particularly weight training

Question 13

What nutritional breakdown is recommended for women with GDM?

Answer 13

33-40% of calories from carbohydrate, protein 20%, fat 40%

Complex carbohydrates rather than simple carbohydrates are less likely to produce postprandial hyperglycemia

Question 14

What is the recommended starting dose for insulin?

Answer 14

0.7-1 unit per kilogram daily in divided doses

Question 15

What is the onset and duration for insulin lispro and aspart?

For regular insulin?

For NPH?

For glargine?

Answer 15

1-15 minutes; 4-5 hours

30-60 minutes; 6-8 hours

1-3 hours; 13-18 hours

1 hour; 24 hours

Question 16

When do you start medication for gestational diabetes?

Answer 16

When 20% or more of capillary blood glucose levels are elevated.

Question 17

What class of medicine is glyburide?

What is the mechanism of action?

Comment on its efficacy compared to insulin.

Answer 17

Sulfonylurea

Binds to pancreatic beta-cell ATP calcium channel receptors to increase insulin secretion and insulin sensitivity of peripheral tissues

Glucose levels do not differ between women treated with insulin versus oral agents and there is no increased short-term maternal or neonatal outcomes

Question 18

What percentage of women treated with glyburide will ultimately require insulin?

Answer 18

20-40%

Question 19

What dose of glyburide is used?

Answer 19

2.5-20 mg daily in divided doses

Question 20

When is antepartum fetal monitoring recommended for GDM?

Answer 20

For women with poor glycemic control. There is no consensus regarding antepartum testing in women with well-controlled GDM.

Question 21

When is delivery recommended for women with GDM?

When is cesarean section offered?

Answer 21

No evidence-based recommendation can be made regarding timing of delivery with diet- or medication-controlled GDM. Expectant management beyond 40 weeks is associated with a 10% shoulder dystocia risk. Locally, we induce at 39 0/7 weeks

CD offered for EFW 4500 g or more. However 588 cesarean deliveries are necessary to prevent one permanent brachioplexus injury.

Question 22

What postpartum screening is recommended?

What value indicates DM?

What level indicates impaired glucose tolerance?

Answer 22

75 g, two hour glucose tolerance test at 6-12 weeks postpartum

Greater than or equal to 200 mg/dL

Between 140 and 199 mg/dL

Question 23

What is recommended for impaired glucose tolerance?

Answer 23

Referral to PCP for management
Weight loss and physical activity counseling
Consider Metformin for impaired fasting glucose and impaired glucose tolerance
Nutrition counseling
Yearly assessment of glycemic status

Question 24

How often should women with GM and normal postpartum screening be followed?

Answer 24

Assess glycemic status every three years

Weight loss and physical activity counseling as needed