Gestational Diabetes Mellitus

Question 1

What are risk factors for GDM?

Answer 1

1) physical inactivity
2) first degree relative w/ DM
3) AA, Latinx, American Indian, Asian-American, Pacific Islander
4) hx macrosomia (>4,000g)
5) hx GDM
6) HTN (>140/90) or rx for HTN
7) HDL <35 or triglyceride >250
8) PCOS
9) AIC≥5.7%
10) insulin resistant conditions
11) hx CVD
12) age>40yo

Question 2

At what BMI should testing occurring?

Answer 2

1) BMI>25

2) BMI >23 (Asian-Americans)

Question 3

When is GDM typically dx’ed?

Answer 3

2nd or 3rd trimester

Question 4

How do the hormones of pregnancy affect development of GDM?

Answer 4

1) promote accumulation of adipose tissue

2) promote insulin resistance during 2nd and 3rd trimesters

Question 5

Which hormones contribute to insulin resistance?

Answer 5

1) human placental lactogen: promotes insulin release from pancreas
2) human placental growth hormone
3) progesterone
4) cortisol
5) prolactin

Question 6

How is glucose transported from mother to fetus?

Answer 6

via facilitated diffusion by insulin-dependent glucose transporters

Question 7

What produces the hormones of pregnancy?

Answer 7

placenta in latter half of pregnancy

Question 8

Why is it difficult for pregnant people to achieve euglycemia?

Answer 8

inability to secrete adequate insulin to compensate for increased insulin resistance –> GDM

Question 9

When and how should pregnant people FIRST be assessed for GDM?

Answer 9

At INITIAL visit using DM hx and assessment of risk factors

Question 10

When is standard testing performed for GDM?

Answer 10

@ 24-28 weeks

Question 11

Describe the 1h GCT

Answer 11

• SCREENING test
• does not require fasting
• 50g glucose PO
• blood draw in 1h

≥130-140 –> glucose tolerance test

Question 12

Describe the 3h GTT

Answer 12

• DIAGNOSTIC test
• NPO 8-10h before test
• 100g glucose PO
• blood draw q1h for 3h

Question 13

What are abnormal ranges for 3h GTT and follow-up?

Answer 13

fasting: 95-105 mg/dL
1h: 180-190 mg/dL
2h: 155-165 mg/dL
3h: 140-145 mg/dL

dx = 2+ abnormal values

• lower value = Carpenter and Coustan criteria
• higher value = National Diabetes Data Group criteria

Question 14

What testing is recommended by WHO but not ACOG?

Answer 14

2h GTT

• combined screening and dx
• 75g glucose PO

1 abnormal = dx

Question 15

What fasting plasma is diagnostic of overt diabetes in early pregnancy?

Answer 15

≥126 mg/dL

Question 16

What A1C is diagnostic of overt diabetes in early pregnancy?

Answer 16

≥6.5%

Question 17

What random fasting glucose is diagnostic of overt diabetes in early pregnancy?

Answer 17

≥200 mg/dL

Question 18

Why should pregnant people avoid caloric/carb restriction?

Answer 18

can lead to ketonuria and ketonemia

Question 19

What are suggested macro percentages to meet 2,000-2,500kcal diet?

Answer 19

• carb: 50-55% total calories
• protein: 20%
• fat: 25-30%

Question 20

List kcal/g for each macro

Answer 20

• carb: 4kcal/g
• protein: 4kcal/g
• fat: 9kcal/g

Question 21

Describe physical activity recommendations

Answer 21

1) moderate intensity aerobic exercise (50-70% max HR) – 150 min/week
AND/OR
2) vigorous exercise (70% max HR) – 90 min/week

Question 22

When should patients check blood glucose during the day?

Answer 22

1) fasting
2) 1-2 hours postprandial (PP)

4x/day

Question 23

What are blood glucose goals?

Answer 23

• fasting: <95
• 1h PP: <130
• 2h PP: <120
• 2am-6am: >60

Question 24

What are blood glucose goals for pts not taking meds?

Answer 24

• before breakfast: 60-90

- before lunch, dinner, bed time snack: 60-105

Question 25

What is ACOG’s tx of choice for GDM?

Answer 25

insulin

Question 26

Describe GDM management w/ insulin

Answer 26

• requires management by physician
• does NOT cross placenta
• recommended for pts w/ BMI>40
• start low and adjust PRN

Question 27

What is important to remember about insulin in the third trimester?

Answer 27

increased insulin demand!

Question 28

What are 2 other tx options for GDM?

Answer 28

1) glyburide: promotes increased insulin secretion

2) metformin: decreases glucose output from liver

Question 29

What are fetal risks of GDM?

Answer 29

1) IUFD
2) macrosomia
3) PEC
4) polyhydramnios
5) operative delivery

Question 30

What are neonatal risks of GDM?

Answer 30

1) congenital anomalies/defects (e.g. fetal cardiac and CNS malformations)
2) macrosomia
3) birth trauma
4) respiratory distress syndrome
5) hypoglycemia
6) hyperbilirubinemia
7) perinatal mortality
8) development of obesity/DM2

Question 31

What is antenatal testing for pts requiring insulin/PO antihyperglycemics and/or have HTN, obesity, other comorbidities?

Answer 31

initiated in 3rd trimester

1) BPP
2) NST
3) AFI
4) +/- periodic EFW evaluation

Question 32

Why is fetal growth monitoring unnecessary in GDM A1?

Answer 32

• can lead to high false positive results –> unnecessary C/S
• concern for fetus having increased abdominal circumference as reflection of increased adiposity

Question 33

What is GDM A1?

Answer 33

managed by diet and lifestyle

Question 34

What is GDM A2?

Answer 34

requires medication (insulin or glyburide)

Question 35

What is antenatal testing for DGM A2?

Answer 35

@32 weeks

- BPP/NST 2x/week

Question 36

What is antenatal testing for GDM A1?

Answer 36

NSTs at term (same as normal pregnancy)

Question 37

According to ACOG, when can C/S be offered?

Answer 37

EFW > 4500g in women w/ GDM

*evidence level C - not great!

Question 38

Describe postpartum management of GDM

Answer 38

75g 2h GTT at 4-12 weeks postpartum

• assesses if pt has overt DM
• use non-pregnancy values

normal: <140mg/dL
impaired: 140-199 mg/dL
diabetes: >200 mg/dL

OR!

fasting blood glucose

Question 39

When should pts w/ GDM deliver?

Answer 39

• @term if antepartal testing reassuring and diabetes stable

- <39 weeks w/ poor/undocumented control –> establish lung maturity w/ amniocentesis