Pregnancy

Question 1

What can material diabetes mellitus cause in the baby?

Answer 1

Macrosomia (birth weight>4kg)

Structural defects (CNS - spina bifida ; skeletal - caudal regression syndrome ; renal - ureteric duplication)

Intrauterine death

Polyhydramnios

Question 2

How does maternal hyperglycaemia cause macronosmia?

Why is this important?

Answer 2

1. Maternal hyperglycaemia passed onto foetus
2. Causes foetal hyperinsulinaemia
3. Insulin is growth factor so baby grows

Has delivery implications

Question 3

What changes are made to diabetes medication in pregnancy?

Answer 3

Consider changing oral therapy to insulin

Question 4

What changes are made to diabetes monitoring in pregnancy?

Answer 4

More regular eye checks (3 monthly rather than annually)

Stricter blood glucose targets

Question 5

What changes are made to labour management in a patient with diabetes?

Answer 5

Ensure strict blood glucose control with IV insulin and IV dextrose

Question 6

What is gestational diabetes?

Answer 6

Condition where women without previous diabetes develops hyperglycaemia in pregnancy

Question 7

At what stage in pregnancy does gestational diabetes usually occur?

Answer 7

3rd trimester

Question 8

What is the pathophysiology of gestational diabetes?

Answer 8

Insulin resistance (by pogesterone and hPL) is a physiological response in pregnancy (ensures sufficient glucose supply to growing foetus)

In predisposed women this progresses to gestational diabetes

Question 9

How is gestational diabetes managed?

Answer 9

Metformin

Some patients may need insulin

Question 10

What follow up tests are done for patients with gestational diabetes and why?

Answer 10

Fasting plasma glucose measurement

Women with gestational diabetes are at high risk of developing T2DM

If fasting plasma glucose measurement is above 7, patient has diabetes

Question 11

What anti-thyroid drugs are used in pregnancy with pre-existing hyperthyroidism?

Answer 11

1st trimester - prophylthiouracil

2nd/3rd trimester - carbimazole

Question 12

What blood test should be offered in the third trimester to patients with hyperthyroidism and why?

Answer 12

TRAb antibodies

TRAb antibodies can cross the placenta and cause transient neonatal thyrotoxicosis

Question 13

What is the differential diagnosis for a pregnant women presenting with vomiting associated with sweating, tachycardia and weight loss?

Answer 13

Hyperemesis of pregnancy

Hyperthyroidism

Question 14

What is the commonest cause of thyrotoxicosis in pregnancy?

Answer 14

Gestational hCG associated thyrotoxicosis

Question 15

What is the pathophysiology of gestational hCG associated thyrotoxicosis?

Answer 15

Human chorionic gonadosrophin is produced by placenta after implantation

It has very similar structure to TSH and can mimic its effects causing hyperthyroidism

Question 16

What is the management of gestational hCG associated thyrotoxicosis?

Answer 16

Usually only lasts 20 weeks

Treat if it persists beyond 20 weeks

Question 17

What happens to the thyroid gland and TFTs in pregnancy? Why? How?

Answer 17

Thyroid enlarges
Primary hyperthyroidism (high T4, low TSH)

Cope with the increased metabolic rate required in pregnancy

Human chorionic gonadotrophin has very similar structure to TSH and stimulates primary hyperthyroidism

Question 18

What hormone has a very similar structure to TSH?

Answer 18

Human chorionic gonadotoprhin (hCG)

Identical a-chain, ß-chain is different

Question 19

What is done to the levothyroxine dose in pregnancy? Why is this done?

Answer 19

Increase by 25µg (as soon as pregnancy suspected)

Thyroid needs to be overactive in pregnancy to meet metabolic needs. An underactive gland can’t cope.

Question 20

What does untreated hypothyroidism in pregnancy risk?

Answer 20

Poor neurological development of the child (cretinism)