Endocrine Disorders in Pregnancy: Changes in Glucose Metabolism and Thyroid Physiology

Question 1

During pregnancy, women become __________ resistant.

Answer 1

insulin

Exception: in the first trimester, women actually become more sensitive to insulin.

Question 2

During pregnancy, women secrete _______ as much insulin to become euglycemic.

Answer 2

two to three times

Question 3

Women with pre-existing diabetes will usually need _________ as much insulin.

Answer 3

two to three times

Question 4

__________ stores deplete much more rapidly in pregnant women, so DKA can happen much more quickly.

Answer 4

Glycogen

Question 5

Early in pregnancy, women are in a ___________ state. This reverses during late pregnancy.

Answer 5

anabolic

Question 6

Describe research on obesity and glucose in pregnancy.

Answer 6

Studies have shown that even obese women without gestational diabetes have higher blood glucose levels during pregnancy than lean women. This occurs because of insulin resistance.

Question 7

Triglycerides elevate by late pregnancy because of ____________.

Answer 7

estrogen

Question 8

What did the HAPO trial show?

Answer 8

It placed women (25,000!) into different grades of insulin sensitivity and analyzed rates of negative outcomes. Their results showed that the more insulin resistance a woman is, the more negative outcomes happened; importantly, there was no cutoff–just a continuum.

Question 9

What effect does gestational diabetes have on the genetics of the infant?

Answer 9

Recent research has shown that GD affects the epigenetics of fetuses, specifically making mitochondria less capable.

Question 10

MRI studies have shown that ___________ is present in infants born to mothers with GD.

Answer 10

intrahepatic fat stores

Question 11

The total thyroid hormone levels ____________ during pregnancy.

Answer 11

increase

Estrogen stimulates the production of TBG. The free T4 levels stay the same, so many women with slight suppressed TSH and increase total thyroid hormone do not need antithyroid meds.

Question 12

In a hypothyroid pregnant woman, you need to give ________.

Answer 12

T4, because babies cannot convert T3 to T4

Question 13

In women who have Hashimoto’s prior to pregnancy, be sure to __________.

Answer 13

increase their levothyroxine doses

Question 14

Gestational hyperthyroidism can be caused by _______.

Answer 14

hCG

Note: this is often seen in women with hyperemesis gravidarum.

Question 15

The increased fetal extraction of glucose is compensated by increased maternal _____________.

Answer 15

lipolysis

Question 16

Pregnant women will have ____________ while fasting, compared to non-pregnant women. However, postprandial levels will be ____________.

Answer 16

lower plasma glucose; higher

Question 17

What three lab values are diagnostic of diabetes?

Answer 17

• Fasting glucose greater than 125 mg/dL
• Random glucose greater than 200 mg/dL
• A1c greater than 6.5%

Question 18

In women with pre-established diabetes, glucose is a major teratogen. Why is this not a problem for women with gestational diabetes?

Answer 18

In GD, glucose is normal during the first trimester. That is the period during which glucose would be a teratogen, so GD does not cause birth defects.

Question 19

Describe the current screening guidelines for gestational diabetes.

Answer 19

All women are screened at 24 weeks with a 50-gram glucose tolerance test. Those with serum glucose greater than 130 mg/dL are then given a three-hour, 100-gram glucose tolerance test. Those with two or more abnormal values are considered GD.

Three hour: 
• Fasting: greater than 95 
•1st: greater than 180
• 2nd: greater than 155 
• 3rd: greater than 140

Question 20

How is GD managed?

Answer 20

Dietary restriction is tried first with postprandial glucose checks. If diet cannot keep glucose within the target range, then glyburide and subcutaneous insulin is used. Glyburide crosses the placenta least well of all the oral hypoglycemics.

Question 21

Which kind of thyroxine should be used in pregnancy?

Answer 21

T4

Fetal brain lacks T3 receptors, so T3 will not replace thyroid hormone deficiency in fetuses.

Question 22

The TSH normally ___________ due to the presence of hCG.

Answer 22

decreases