Thyroid disease and pregnancy

Question 1

what can thyroid disease cause in fertility

Answer 1

anovulatory cycles- release of egg from ovaries does not occur - reduced fertility

Question 2

effect of thyroid on pregnancy

Answer 2

increased demand; increase in size, increased T4 production just to maintain normal concentration

Question 3

what is maternal thyroixine important for

Answer 3

neonatal developmetn

Question 4

effect of plasma binding protein

Answer 4

increases

Question 5

if have pre existing hypothyroidism what must happen

Answer 5

increase thyroxine dose by 25mcg as soon as pregnancy suspected
* Chech TFTs monthly for first 20 weeks then 2 monthly until term
* The average dose increase is by 50% by 20 weeks
Aim for TSH <3 mU/l

Question 6

complications of untreated hypothyroidism in pregnancy

Answer 6

• Increased abortion, preeclampsia, abruption, postpartum haemorrhage, preterm labour
  Impacts on foetal neurophysical development - average of 7 IQ points less in children of untreated hypothyroid mothers vs normal mothers

Question 7

causes of hyperthyroidism in pregnancy

Answer 7

• Most common cause in this age group (fertile women) is Graves’ disease
  Other causes include TMNG, toxic adenoma and thyroiditis

Question 8

complications of hyperthyroidism in pregnancy

Answer 8

• Infertility/ammenorhoea
• Spontaneous miscarriage
• Stillbirth
• Thyroid crisis in labour
  Transient neonatal thyrotoxicosis

Question 9

management of hyperthyroidism in pregnancy

Answer 9

• Wait and see (supportive management)
  ○ If hyperemesis, will settle
  ○ Graves may settle as pregnancy suppresses autoimmunity
  ○ Check TRAb antibodies - if present alert neonatologist as TRAb antibodies can cross the placenta and cause neonatal transient hyperthyroidism
• β-blockers if needed
• LOW DOSE antithyroid drugs - wait as late as possible due to side effects on foetus
  ○ Propylthiouracil 1st trimester
  ○ Carbimazole 2/3rd trimester

Question 10

investiagtions for post partum thyroiditis

Answer 10

• Thyroid function tests
• Thyroid antibody tests
  Scintigraphy scan

Question 11

management of hyperthyroid post partum

Answer 11

• No treatment for hyperthyroid phase, if symptomatic hypothyroid treat with thyroxine
  Should eventually be able to stop thyroxine but if patient is still on thyroxine after a year it is likely they will need it long term

Question 12

clinical presentation of hyperthyroidism post partum

Answer 12

• After delivery, the mother develops transient over-active thyroid, classically at around 6 weeks, and then at around 3 months has an underactive thyroid
• Will develop small, diffuse, nontender goitre
• Hypothyroid phase associated with neonatal depression
  Can persist up to 1 year post partum
  occurs wihtin 6 months of giving birth

Question 13

what does high HCG mimic

Answer 13

hyperthyroidism

Question 14

how to distinguish hyperemesis from hyperthyroidism

Answer 14

high hcg , low tsh
Not TRab antibody positive
Resolves by 20 wks gestation ie improves
Only treat if persists > 20 wk

Question 15

what is Gestational hCG-asscociated Thyrotoxicosis

Answer 15

subset of hyperemetic patients with clinical and biochemical hyperthyroidism in early pregnancy

Question 16

what is hyeremesis

Answer 16

severe nausea, vomitting and weight loss during pregnancy