Diabetes and Endocrinology in Pregnancy

Question 1

Key events in the ovarian cycle?

Answer 1

Day 1 is when menstruation begins

1. Follicular growth occurs at day 10 and oestradiol is produced
2. Ovulation occurs at day 14 and LH secretion peaks
3. Luteal function begins and the follicle develops the corpus luteum; progesterone and oestradiol are produced

Question 2

Hormone produced during progression from follicle to progesterone?

Answer 2

Follicle - oestradiol

Implanted fertilised ovum - HCG (pregnancy test basis)

Corpus luteum - progesterone

Question 3

Hormones produced by the placenta?

Answer 3

Human Placental Lactogen (hPL)

Placental progesterone

Placental oestrogens

Question 4

Hormones produced by the pituitary, in relation to pregnancy?

Answer 4

Prolactin (lactogen)

Question 5

Development of gestational diabetes?

Answer 5

Progesterone and hPL produced during pregnancy cause insulin resistance in the mother

In a predisposed individual, the BG rises and gestational diabetes occurs

Question 6

3 types of diabetes in pregnancy?

Answer 6

1. T1DM
2. T2DM
3. Gestational diabetes mellitus (tends to occur in the 3rd trimester)

Question 7

When does foetal organogenesis begin?

Answer 7

5 weeks and possibly earlier

Question 8

Complications of diabetes in pregnancy?

Answer 8

Congenital malformation

Prematurity

Intra-uterine growth retardation (IUGR) - small baby

Macrosomia - large baby

Polyhydramnios (excessive amniotic fluid)

Intrauterine death

Question 9

Complications of diabetes in pregnancy for the neonate?

Answer 9

Respiratory distress due to immature lungs

Hypoglycaemia causes fits, which may cause brain damage

Hypocalcaemia causes fits, which may cause brain damage

Question 10

CNS defects that can occur due to diabetes in pregnancy?

Answer 10

Anencephaly (absence of a major portion of the brain, skull, and scalp that occurs during embryonic development)

Spina bifida

Question 11

Skeletal abnormalities that can occur due to diabetes in pregnancy?

Answer 11

Caudal regression syndrome

Question 12

Genital and GI abnormalities that can occur due to diabetes in pregnancy?

Answer 12

Ureteric duplication

Question 13

How does macrosomia occur?

Answer 13

Maternal hyperglycaemia causes foetal hyperglycaemic and hyperinsulinaemia

In the 3rd trimester, the foetus produced its own insulin (a major growth factor) but, in addition to the extra insulin, this causes macrosomia and neonatal hypoglycaemia

Question 14

Pre-pregnancy counselling for T1DM or T2DM patients?

Answer 14

Good BG control pre-conception limits the risk of congenital malformation

Question 15

Management of a pregnancy in T1DM and T2DM?

Answer 15

Folic acid (5mg); in a non-diabetic patient, the dose is only 400mcg

Consider a change from oral medication to insulin

Regular eye checks are required (3 monthly) due to accelerated retinopathy

Question 16

How should BP be managed in pregnancy?

Answer 16

Avoid ACEIs and statins

For BP control, use:
• Labetalol
• Nifedipine
• Methyldopa

Question 17

Management of pregnancy for all (T1DM, T2DM and GDM)?

Answer 17

Follow a diabetic diet and aim for BG control:
• Pre-meal: <4 - 5.5 mmol/L
• 2 hours post-meal: <7 mmol/L

Monitor HbA1c and BP

Maintain BG during labour with IV insulin and IV dextrose

Question 18

Pharmacological treatment of GDM?

Answer 18

1. Lifestyle Mx

2. Metformin; they may need insulin

Question 19

Follow-up of GDM?

Answer 19

A glucose tolerance test is done 6 weeks post-natal to ensure resolution of DM

If it has not resolved, they have T2DM

Question 20

Implications of GDM?

Answer 20

A marker of insulin resistance

With GDM, 50% go on to develop T2DM within 10-15 years; this is even higher for obese patients

Some patients, e.g: if they are thin, may actually have T1DM

Question 21

Methods of preventing diabetes following GDM?

Answer 21

Keeping weight as low as possible with aerobic exercise and a healthy diet:
• Low refined sugar
• Predominant sugar
• Low saturated fat
• Low energy foods 

Metformin, acarbose, etc, can be considered

Annual fasting glucose must be checked

Question 22

Thyroid demand during pregnancy?

Answer 22

Increased demand during pregnancy and maternal thyroxine is important for neonatal development in early pregnancy, esp. of the brain

Thyroid gland increases in size and there is increased T4 production, to maintain normal conc.

Question 23

What is anovulatory cycle?

Answer 23

Menstrual cycle during which the ovaries do not release an oocyte; thus, ovulation does not occur

Hype and hyperthyroidism can cause this

Question 24

Effect of pregnancy on thyroid hormones?

Answer 24

Plasma protein binding increases

Question 25

Effect of hCG in pregnancy?

Answer 25

Free T4 (fT4) increases in some pregnancies Low TSH in some pregnancies Hyperemesis gravidarum can occur

Question 26

What is hyperemesis gravidarum?

Answer 26

Severe nausea and vomiting during pregnancy, such that weight loss and dehydration occur

Question 27

Biochemistry in hyperemesis gravidarum?

Answer 27

hCG high Majority have abnormal TSH/fT4

Question 28

Action of TSH and hCG?

Answer 28

TSH and hCG both increase thyroxine, which suppresses TSH

Question 29

Structural similarities and differences between TSH and hCG?

Answer 29

Both are 2 chain peptides in which the: • α-chain is identical • β-chain is different

Question 30

How to manage pre-existing hypothyroidism in pregnancy?

Answer 30

INCREASE thyroxine dose by 25mcg AS SOON AS pregnancy is suspected (do not wait for blood tests) Check TFTs monthly for the 1st 20 weeks and then every 2 months until term

Question 31

TSH aim in pregnancy?

Answer 31

<3 mU/L

Question 32

Risk of untreated hypothyroisidm in pregnancy?

Answer 32

Foetal neuropsychological development, e.g: lower IQ ``` Increased risk of: • Abortion • Pre-eclampsia • Abruption • Post-partum haemorrhage • Pre-term labour ```

Question 33

Risk of hyperthyroidism?

Answer 33

Infertility Spontaneous miscarriage Stillbirth Thyroid crisis (AKA storm) in labour Transient neonatal thyrotoxicosis (a jittery baby that does not feed properly or put on weight)

Question 34

Causes of thyrotoxicosis in pregnancy?

Answer 34

* Grave's disease * Toxic multi-nodular goitre (TMNG), toxic adenoma * Thyroiditis

Question 35

How to distinguish hyperemesis from hyperthyroidism?

Answer 35

Hyperemesis has: • Increased hCG and decreased TSH • Not TRab antibody +ve • IMPROVES/resolved by 20 weeks gestation (on the other hand, hyperthyroidism worsen as time progresses)

Question 36

Treatment of thyrotoxicosis in pregnancy?

Answer 36

ONLY treat if it persists >20 weeks (supportive Mx in this time); if it settles, it was hyperemesis. Also, Grave's may settle as pregnancy suppresses autoimmunity β-blockers, if required LOW DOSE anti-thyroid drugs: • 1st trimester - propylthiouracil • 2/3rd trimester - Carbimazole ....WAIT AS LATE AS POSSIBLE BEFORE STARTING THESE

Question 37

Problems with carbimazole in pregnancy?

Answer 37

``` Can cause: • Embryopathy in 1st trimeter • Scalp abnormalities • GI abnormalities • Choanal & oesophageal atresia ```

Question 38

Problems with propylthiouracil in pregnancy?

Answer 38

Risk of liver toxicity Best to avoid, except possibly in the 1st trimester and then switch to carbimazole

Question 39

TRAb antibodies in pregnancy?

Answer 39

Check these in the 3rd trimester and, if present, suspect thyroid dysfunction in the fetus These antibodies can cross the placenta and cause NEONATAL TRANSIENT HYPERTHYROIDISM

Question 40

Describe post-partum thyroiditis

Answer 40

Tends to occur ~6-8 weeks following labour At 4-6 months, female develops hypothyroidism, so she is not treated before this Should recover ~12 months post-partum, although some develop persistent hypothyroidism, i.e: beyond 1 year

Question 41

Presentation of post-partum thyroiditis?

Answer 41

Small, diffuse, non-tender goitre

Question 42

``` What is the thyroid status of the pregnancy woman at 10 weeks gestation: • fT4 15 (10-20) • TT3 3.4 (up to 2.6) • TSH 0.3 (0.4-4) ? ```

Answer 42

hCG-mediated suppression of TSH is most likely (this is normal) However, it could also be early Grave's disease