Glucose Regulation in Pregnancy

Question 1

What are the effects of high levels of glucose in early pregnancy?

Answer 1

glucose toxicity causing miscarriage, congenital defects

Question 2

What are the normal BGL limits outside and inside of pregnancy?

Answer 2

outside: 4.5 - 5.5 mmol/L
inside: >5.1mmol/L

Question 3

How does insulin transport glucose in to the cell?

Answer 3

insulin binds to insulin binding receptor causing downstream signalling -> translocation of GLUT4 to plasma membrane allowing influx of glucose out of blood into tissue

Question 4

How does insulin affect weight in early pregnancy?

Answer 4

Insulin increases fat and glycogen storing

Question 5

What hormones promote beta cell expansion and increased insulin production in early pregnancy?

Answer 5

estrogen, progesterone, HPL, GH

Question 6

What hormone promotes lipogenesis to increase fat stores and what is the name of this stage in pregnancy?

Answer 6

insulin, anabolic phase

Question 7

Describe the catabolic processes of later pregnancy?

Answer 7

tissues become insulin resistant causing release of fat and glycogen stores to provide energy to fetus

Question 8

why is fasting plasma glucose in pregnant people not higher than non-pregnant people?

Answer 8

the glucose is not left in the maternal blood, it is transferred to the fetus

Question 9

What is the average difference in BGL between maternal and fetal blood and why?

Answer 9

maternal blood roughly 1mmol/L higher than fetus to maintain concentration gradient

Question 10

How does a cell become insulin resistant?

Answer 10

decrease in insulin receptors and derangement in intracellular signalling cascades following receptor activation (eg impaired GLUT4 translocation)

Question 11

What are the functions of HPL and PGH in relation to insulin?

Answer 11

HPL increases beta cell number, size and survival, stimulating insulin release
PGH causes resistance

Question 12

Discuss the roles of HPL and PGH in GDM.

Answer 12

if there is an imbalance between beta cell expansion (HPL) and insulin resistance (PGH) this can lead to GDM, eg too much insulin resistance and not enough insulin

Question 13

Why is pre-existing DM more dangerous than GDM?

Answer 13

High BGL occurs when pregnancy is most vulnerable, glucose toxicity results in NTDs, fetal death

Question 14

differentiate pre-existing DM levels from GDM levels

Answer 14

fasting BGL: pre-existing >7mmol/L whereas GDM 5.1-6.9mmol/L
2h post 75g PO glucose: pre-existing >11.1mmol/L and GDM 8.5- 11.1mmol/L