Gestational Diabetes

Question 1

Who do you screen for gestational diabetes?

Answer 1

All pregnant patients.
Early screening is recommended in these patients:

• Physical inactivity
• First-degree relative with diabetes
• High-risk race or ethnicity (eg, African American, Latino, Native American, Asian American, Pacific Islander)
• Have previously given birth to an infant weighing 4,000g (approximately 9 lb) or more
• Previous gestational diabetes mellitus
• Hypertension (140/90 mm Hg or on therapy for hypertension)
• High-density lipoprotein cholesterol level less than 35 mg/dL (0.90 mmol/L), a triglyceride level greater than 250 mg/dL (2.82 mmol/L)
• Women with polycystic ovarian syndrome
• A1C greater than or equal to 5.7%, impaired glucose tolerance, or impaired fasting glucose on previous testing
• Other clinical conditions associated with insulin resistance (eg, prepregnancy body mass index greater than 40 kg/m2, acanthosis nigricans)
• History of cardiovascular disease

Question 2

What are the risk factors for gestational diabetes?

Answer 2

Physical inactivity
First-degree relative with diabetes
High-risk race or ethnicity (eg, African American, Latino, Native American, Asian American, Pacific Islander)
Have previously given birth to an infant weighing 4,000g (approximately 9 lb) or more
Previous gestational diabetes mellitus
Hypertension (140/90 mm Hg or on therapy for hypertension)
High-density lipoprotein cholesterol level less than 35 mg/dL (0.90 mmol/L), a triglyceride level greater than 250 mg/dL (2.82 mmol/L)
Women with polycystic ovarian syndrome
A1C greater than or equal to 5.7%, impaired glucose tolerance, or impaired fasting glucose on previous testing
Other clinical conditions associated with insulin resistance (eg, prepregnancy body mass index greater than 40 kg/m2, acanthosis nigricans)
History of cardiovascular disease

Question 3

How do you screen for gestational diabetes?

Answer 3

1 hour glucose tolerance testing with 50 grams of sugar

Although controversial, hemoglobin A1c can be used.

Question 4

What are the diagnostic gestational diabetes?

Answer 4

3 hour glucose tolerance testing with 100 grams. 
Carpenter and Coustan conversion: 
Fasting <95mg/dl 
1 hour glucose <180mg /dl 
2 hour glucose <155mg/dl 
3 hour glucose <140mg/dl

Question 5

Once gestational diabetes is diagnosed, describe how you counsel the patient about this diagnosis.

Answer 5

Gestational diabetes can increase morbidity in pregnancy if uncontrolled. These complications include hypertensive disorders such as preeclampsia, there is an increased risk for cesarean section, fetal macrosomia, fetal hyperbilirubinemia, hypocalcemia, hypoglycemia. Moreover, there is an increased risk for operative delivery, shoulder dystocia, birth trauma.

Question 6

What are the fetal and maternal risks due to gestational DM?

Answer 6

There is an increased risk of cesarean section and progression to diabetes later in life for the patient.

There is an increased risk of birth trauma fetal macrosomia, fetal hyperbilirubinemia, hypocalcemia, hypoglycemia.

Question 7

What are the goals of therapy for gestational DM?

Answer 7

Fasting less than 95mg/dl
1 hour glucose postprandial less than 140mg/dl
2 hour glucose postprandial less than 120mg/dl

Question 8

What is your first line medication for gestational DM?

Answer 8

Insulin has historically been considered the standard for diabetes treatment in pregnancy. Insulin does not cross the placenta and can help to achieve a better glycemic control. The goal for glycemic control include fasting less than 95mg/dl and a 1 hour postprandial less that 140 mg/dl or 2 hour postprandial less than 120mg/dl.

Metformin will fail about 50% of the time if used by itself

Question 9

When and how do you screen for diabetes postpartum?

Answer 9

2 hour oral glucose tolerance test with 75 grams between 4-12 weeks of the postpartum period.

• if blood sugar is normal (glucose 70-99mg/dl for fasting and <140mg/dl for 2 hour) then glycemic status will need to be assessed every 3 years
• if blood sugar is abnormal (glucose >126mg/dl for fasting and >200mg/dl for 2 hour) then patient needs to be referred for diabetic management
• if impaired blood sugar is noted (glucose 100-125mg/dl for fasting and 140-199mg/dl for 2 hour) then should be referred for weight loss, nutrition and metformin consideration as well as yearly assessment of glycemic status

Question 10

HAPO study:

Answer 10

Population: pregnant women who underwent

Intervention: 2 hour 75 gram glucose tolerance testing
with fasting less than 105 and 2 hour glucose more than 200

Control: same as above

Outcome: birth weight above 90%ile, cesarean delivery, neonatal hypoglycemia

Conclusion: there is an association between maternal glucose below diagnostic levels of diabetes in pregnancy and increased birth weight in the neonate.