Endocrinopathies in pregnancy Flashcards
True or false?
All women of reproductive age with endocrine disease should have access to preconception specialist to make choices about pregnancy.
True
What hormone is produced during pregnancy?
Human chorionic gonadotrophin hCG
In the first trimester what hormones are produced?
Progesterone
Oestradiol
Free estriol
Human placental lactogen
These can affect TSH levels.
Is there a separate pregnancy range for TSH?
Yes
What are the metabolic changes in pregnancy?
- Increased erythropoetin, cortisol, noradrenaline
- High cardiac output
- Plasma volume expansion
- High cholesterol and triglycerides
- Pro thrombotic and inflammatory state
- Insulin resistance
Name some of the gestational syndromes
- Pre-Eclampsia
- Gestational Diabetes
- Obstetric cholestasis
- Gestational Thyrotoxicosis
- Transient Diabetes Insipidus
- Lipid disorders
- Postnatal depression
- Postpartum thyroiditis
- Postnatal autoimmune disease
- Paternal Disease
When does foetal thyroid follicle and thyroxine synthesis occur?
Weeks 10.
The hypothalamus-pituitary-thyroid axis matures by when?
At 15-20 weeks.
What regulates neurogenesis, migration and differentiation between weeks 0-12?
Maternal T4
Describe the relative changes in maternal and foetal thyroid function during pregnancy.
The effects of pregnancy on the mother include a marked and early increase in hepatic production of thyroxine-binding globulin (TBG) and placental production of hCG.
The increase in serum TBG in turn increases T4 concentration.
hCG has thyrotropin-like activity and stimulates maternal T4 secretion.
The transient hCG-induced increase in serum free T4 inhibits maternal secretion of thyrotropin.
What happens in women with normal thyroid function during pregnancy?
Increase in T3 (triiodothyronine) and T4 (thyroxine). This inhibits TSH in the first trimester due to high hCG.
Why does high hCG level inhibits TSH production?
Because there is partial structural similarity so hCG stimulates TSH-R.
Why are thyroxine requirements higher in pregnancy?
A large plasma volume and thus an altered distribution of thyroid hormone, increased thyroid hormone metabolism, increased renal clearance of iodide, and higher levels of hepatic production of thyroxine-binding globulin (TBG) in the hyperestrogenic state.
TSH, LH, FSH, hCG have what in common?
Their alpha subunit is the same but they differ in the beta subunits.
Prevalence of Hypothyroidism during pregnancy
During pregnancy: 2-3%
Overt hypothyroidism: 0.3-0.5%
Subclinical: 2-3%
What are the signs and symptoms of hypothyroidism?
Predate the pregnancy.
Weight gain, cold intolerance, poor concentration, poor sleep pattern, dry skin, constipation, tiredness.
What is the TSH specific range for the first trimester?
0.1-2.5 mlU/L
What is the TSH specific range for the second trimester?
0.2-3.0 mlU/L
What is the TSH specific range for the third trimester?
0.3-3.0/3.5 mlU/L
How often are patients seen for 20 weeks of gestation?
4 weekly
How does levothyroxine dosage changes during pregnancy?
It goes up during pregnancy - then needs to go back to pre-pregnancy levels after delivery.
Requirements go up in the beginning up to a 125 micrograms until test can be carried out.
In high risk women, TSH needs to be checked as soon as pregnancy is confirmed with TPOAb if TSH is what?
If TSH is between 2.5-10 mU/L.
What are the primary causes of hypothyroidism
Autoimmune
Hashimoto’s disease
Atrophic thyroiditis
Drugs
Lithium
Amiodarone
Iodine deficiency
Congenital
Toxic nodule
What are the transient causes of hypothyroidism?
Post partum thyroiditis
Subacute thyroiditis
What is the secondary cause of hypothyroidism?
Hypopituitarism
How does hypothyroidism affect pregnancy?
Inadequate treatment:
- Gestational hypertension
- Placental abruption
- Post partum haemorrhage
If untreated:
- Low birth weight
- Preterm delivery
- Neonatal goitre
- Neonatal respiratory distress
What is the course of action in hypothyroidism during pregnancy?
Preconception counselling ideal pre-conception TSH <2.5 mIU/L
Increase dose by 30 %
arrange TFT early preg and titrate
women require a dose increase in their thyroxine during pregnancy
If overt in pregnancy aim to normalise asap
Commence at 50-100mcg measure TFT at 4-6 weeks.
Targeted screening
Age >30
BMI >40
Miscarriage preterm labour
Personal or family history
Goitre
Anti TPO
Type 1 DM
Head and neck irradiation
Amiodarone, Lithium or contrast use
What is the prevalence of Hyperthyroidism in pregnancy?
0.1-0.4%
Which gender is more affected?
Females 2%
Hyperthyroidism is 1 in how many pregnancies?
1 in 500
What is the main cause of hyperthyroidism?
Graves’ disease (85-90%
What re the less common causes of hyperthryoidism?
Toxic adenoma
MNG
Gestational thyrotoxicosis
Trophoblastic neoplasia
TSH-oma
How does hyperthyroidism affect the pregnancy?
If inadequately treated:
- IUGR (intrauterine growth restriction)
- Low birth weight
- Pre-eclampsia
- Preterm delivery
- Risk of stillbirth
- Risk of miscarriage