Endo Disorders of Pregnancy

Question 1

How does insulin response change during pregnancy? (2)

Answer 1

• Insulin sensitivity increases in 1st trimester
  
  • Store fat while fetus is very small
• Insulin resistance occurs in 2nd and 3rd trimester
  
  • Less glucose taken up by mother’s tissues, so can send glucose to growing baby

Question 2

Healthy women maintain their sugar levels normal throughout pregnancy

Question 3

Name 2 reasons that obese women have bigger babies.

Answer 3

Higher glucose levels

Higher TG levels

*This occurs even if the women don’t have gestational diabetes

Question 4

What maternal glucose disorder produces major organ malformations?

Answer 4

Undiagnosed T2D during pregnancy

Question 5

Compare the effect on the baby of undiagnosed T2D and gestational diabetes

Answer 5

Undiagnosed Type II diabetes -> organ malformations

Gestational diabetes -> big babies

Question 6

How do we define GDM? (2)

Answer 6

Glucose intolerance recognized for the first time during pregnancy

*Excluding women with A1C above 6.5, FBG over 125, or random over 200 (overt diabetes)

Question 7

What is the pathophysiology of gestational diabetes?

Answer 7

1. Pregnancy causes insulin resistance
2. Beta cells cannot produce sufficient insulin to compensate for insulin resistance
3. Hyperglycemia

Question 8

What should you consider in thin women with gestational diabetes?

Answer 8

They may have late onset Type 1 Diabetes instead

Question 9

What is the major risk to the mother of gestational diabetes?

Answer 9

50% of mothers with GDM go on to develop T2D in the next 10 years

Question 10

How should you manage GDM during pregnancy? (2)

How should you manage GDM post-partum? (3)

Answer 10

During pregnancy, lifestyle changes & insulin if necessary

After pregnancy,

1. Postpartum oral glucose tolerance test
2. Lifestyle changes & primary prevention
3. Contraception

Question 11

How do glucose and TG’s get across the placenta?

How does maternal insulin cross the placenta?

Answer 11

Glucose and TG’s freely diffuses across placenta

Maternal insulin cannot cross placenta

Question 12

Name 4 potential effects on the baby of GDM

(size, glucose, heart, lungs)

Answer 12

• Macrosomia (big baby)
• Hyperglycemia in utero, followed by immediate hypoglycemia
• Cardiac hypertrophy
• Respiratory distress syndrome due to lung immaturity

Question 13

How are TSH, TBG, total T4, and free T4 affected by pregnancy?

What causes this?

Answer 13

• TSH is low early in pregnancy and later normalizes
  
  • due to hCG
• TBG and total T4 increase
  
  • due to estrogen
• Normal T4

Question 14

A woman with hx of total thyroidectomy becomes pregnant. How should you adjust her levothyroxine dose?

Answer 14

Increase

More will be bound (increased TBG) and more will get degraded (placenta)

Question 15

How are hyperemesis and thyroid function connected?

Answer 15

• Hyperemesis is due to high bHCG
• High bHCG can cause hyperthyroidism due to binding at TSH receptor
• Both occur early in pregnancy (when hCG is highest)

Question 16

Describe the pathogenesis of postpartum thyroiditis

Answer 16

1. Anti-TPO Ab’s (Hashimoto’s) are suppressed during pregnancy
2. After childbirth, rebound high levels of Ab’s
3. Rapid destruction of thyroid causes hormone release and ensuing thyrotoxicosis
4. Hyperthyroidism occurs initially, followed by hypothyroidism

Question 17

Where is fetal insulin from?

How is this affected by GDM?

Answer 17

• Fetus synthesizes its own insulin
  
  • Mom’s can’t cross the placenta
• However, glucose can freely cross placenta
• GDM -> hyperglycemia in baby -> high fetal insulin production -> later insulin resistance

Question 18

Does mom’s amount of thyroid hormone synthesis change during pregnancy?

Answer 18

YES

Free thyroid hormone stays the same, but there is more TBG and so more thyroid hormone must be made total

Question 19

Is postpartum thyroiditis a hyperthyroid or hypothyroid state?

Answer 19

First hyperthyroid, then hypothyroid later

*BUT, it’s never increased production of thyroid hormones (only increased release)