What is the current thinking behind gestational DM?
May be an already overlying DM that is only picked up in pregnancy (or exacerbated by it)
What is the white classification system of DM in pregnancy?
Old classification of DM that is no longer used in practice, but still in some research settings
What is the most common medical complication in pregnancy?
DM
In what ethnicities is the prevalence of gestational DM the highest?
Hispanics
Asians
Blacks
What are the three ways to diagnose DM?
- Random over 200
- Fasting over 126
- HbA1C more than 6.5%
How do you diagnose gestational DM? What indicates a positive test?
Two step strategy:
- one hour 50g glucose challenge.
- If higher than 130, then proceed to 100g, 3 hour test, with a blood draw every hour
What indicates a positive 100 g, 3 hour glucose tolerance test?
If 2 or more blood draws over the 3 hour period, then positive
When in gestation does a mother undergo the glucose tolerance test?
Between 24-28 weeks
What happens if only one of the values of the 100g 3 hr glucose tolerance test is abnormal?
May have increased complications, despite not having true gestational DM
A BMI over what value is a risk factor for gestational DM?
30
What are the two conditions that may predispose to GDM?
- Prediabetes
- PCOS
True or false: if a mother has GDM in a previous pregnancy, she will likely get it again with the next pregnancy
True
Women over what age have a risk for developing GDM?
35
How can you differentiate between GDM, and underlying DM?
GDM does not occur until late in the pregnancy–thus if test is positive early, more likely to be underlying DM
What is the 1 step OTT? When is this performed? What indicates a positive result?
75g of glucose performed at 24-28 weeks, and assessed 2 hours later.
If the first draw is higher than 180, or the 2 hour draw is higher than 153, then positive
What is the “goal” of the maternal body early on in the pregnancy?
accumulate fat for when the fetus grows in the later stages, since this is when most growth occurs
What happens to insulin sensitivity early on in the pregnancy? Late?
Increased sensitivity early on to store fat.
Decreases later
When in pregnancy does insulin resistance begin to increase?
15-20 weeks
How often should you f/u with GDM pts? Why?
Weekly, since insulin needs vary so much
What is the main hormone that influences GDM?
Human placental lactogen
What is adiponectin, and what is its role in GDM?
Protein synthesized by adipocytes that increases insulin sensitivity.
Decreases with GDM
True or false: nearly every pregnancy complication has an increased chance with GDM
true
Who is at risk for stillborns: GDM or prediabetics?
Prediabetics
When in the pregnancy is GDM particularly bad on the fetus? Why?
First trimester, since this is when organogenesis is largely occurring
What is the relationship between vascular disease of GDM, and the risk of adverse fetal outcomes?
Positively correlated
What is the equation for relative risk?
he ratio of the probability of an event occurring (for example, developing a disease, being injured) in an exposed group to the probability of the event occurring in a comparison, non-exposed group.
What happens to the rate of malformations with increasing HbA1C at conception?
Increases
What are the two factors that lead to the development of an overgrown fetus with GDM?
Hyperglycemia and hyperinsulinemia in utero
What happens to neonatal BG levels when it is born? Why?
Drop d/t the loss of high BG levels of the mother, and oversecretion of insulin
How do you measure C-peptide levels of the fetus?
Umbilical cord sampling
What happens to the risk of the child born to a GDM mother of developing DM by adolescents?
6x
What causes the heart defects in children born to GDM mothers?
Deposition of glycogen in the heart, causing hypertrophy
What is the effect of hyperinsulinemia of the fetus on lung maturation?
Insulin inhibits surfactant production = increased risk of NRDS
What causes the increase in the incidence of jaundice in children born to GDM mothers?
Polycythemia d/t hyperglycemia
What, generally, were the results of the HAPO study?
Mothers who had only 1 abnormal reading on a OGTT–which is not a positive test– had an increase in fetal morbidity
What percent of mothers who develop GDM will develop DM II over 10 years?
70%
What is the average reduction of HbA1c with appropriate measures?
2.43%
What is the rule of thumb when correlating HbA1C levels to average BG levels?
8% = 180 mg/dL
1% change is about 30 mg/dL
Why is there an increase in shoulder dystocia with GDM?
Big baby coming out
What is the recommended carb intake for GDM women?
Less than 50% of diet
What is the main treatment for GDM?
Diet and exercise
How do you treat GDM?
- If on insulin, maintain tight control
- Continue oral hypoglycemia agents
How many times should GDM mother monitor their BG levels?
4x/day
What are the goal fasting and 2 hr postprandial BG levels for GDM mothers?
- Fasting = less than 95
- 2 hr Postprandial = Less than 120 (1 hr less than 130)
What are the three oral hypoglycemics that can be prescribed to a GDM mother?
- glyburide
- MEtformin
- ACarbose and others
When should you stop the pharmacotherapy for GDM? When should she follow up, and what should be done?
- Stop postpartum
- 6-8 weeks f/u and do OGTT
If the 6-8 week f/u OGTT is positive, then what? What if negative?
Positive = new DM Negative = repeat q 3 years
What other lab value should be obtained for f/u postpartum GDM mothers?
TSH