Endocrine Disorders in Pregnancy: Changes in Glucose Metabolism and Thyroid Physiology Flashcards
During pregnancy, women become __________ resistant.
insulin
Exception: in the first trimester, women actually become more sensitive to insulin.
During pregnancy, women secrete _______ as much insulin to become euglycemic.
two to three times
Women with pre-existing diabetes will usually need _________ as much insulin.
two to three times
__________ stores deplete much more rapidly in pregnant women, so DKA can happen much more quickly.
Glycogen
Early in pregnancy, women are in a ___________ state. This reverses during late pregnancy.
anabolic
Describe research on obesity and glucose in pregnancy.
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.
Triglycerides elevate by late pregnancy because of ____________.
estrogen
What did the HAPO trial show?
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.
What effect does gestational diabetes have on the genetics of the infant?
Recent research has shown that GD affects the epigenetics of fetuses, specifically making mitochondria less capable.
MRI studies have shown that ___________ is present in infants born to mothers with GD.
intrahepatic fat stores
The total thyroid hormone levels ____________ during pregnancy.
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.
In a hypothyroid pregnant woman, you need to give ________.
T4, because babies cannot convert T3 to T4
In women who have Hashimoto’s prior to pregnancy, be sure to __________.
increase their levothyroxine doses
Gestational hyperthyroidism can be caused by _______.
hCG
Note: this is often seen in women with hyperemesis gravidarum.
The increased fetal extraction of glucose is compensated by increased maternal _____________.
lipolysis
Pregnant women will have ____________ while fasting, compared to non-pregnant women. However, postprandial levels will be ____________.
lower plasma glucose; higher
What three lab values are diagnostic of diabetes?
- Fasting glucose greater than 125 mg/dL
- Random glucose greater than 200 mg/dL
- A1c greater than 6.5%
In women with pre-established diabetes, glucose is a major teratogen. Why is this not a problem for women with gestational diabetes?
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.
Describe the current screening guidelines for gestational diabetes.
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
How is GD managed?
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.
Which kind of thyroxine should be used in pregnancy?
T4
Fetal brain lacks T3 receptors, so T3 will not replace thyroid hormone deficiency in fetuses.
The TSH normally ___________ due to the presence of hCG.
decreases
