Thyroid

Question 1

What is the leading cause of preventable neurodevelopmental defects?

Answer 1

Iodine deficiency
- in these areas thyroid nodules have been reported in up to 30% of pregnant women.

-in regions of mild to moderate iodine deficiency pregnant women are also at increased risk of development of goiter and thyroid disorders

-if iodine low then MC aetiology is autoimmune thyroid disorders

Question 2

What is euthyroidism with thyroid autoimmunity associated with

Vs

Thyroid auto immunity with thyroid dysfunction

Answer 2

euthyroidism with thyroid autoimmunity associated with :

Increased risk of miscarriage
Preterm birth
Portpartum thyroiditis

Vs

Thyroid auto immunity with thyroid dysfunction:

Increased risks of PET and GDM

Question 3

What to do if nodules found in pregnancy on thyroid? Or goiter

Answer 3

Assess local symptoms such as tracheal compression, malignancy, hyperthyroidism exclude

Question 4

What is the upper limit of TSH in pregnancy

Answer 4

4 mU/L in pregnancy

Question 5

What to test in pregnancy for thyroid and when

Answer 5

TSH and fT4 - in the 1st trimester , asap in pregnancy

IF:
- already known positive for TPOAb but euthyroid - should be offered testing in 1st trimester at first contact and at 20w of preg to detect development of hypothyroidism

Other people:
- personal hx of thyroid condition of insult

-autoimmune conditions ; T1DM, SLE, Anti Ro and LA pos, Anti phosphlipid syndrome

-Previous late preg loss: stillbirth, second trimester miscarriage

Question 6

What are the risk of hypothyroidism in preg

Answer 6

0.2-1% ,including undiagnosed , partially treated and adequately treated hypothyroidism

• if untreated or not treated well, risk of spontneous miscarriage, perinatal death, PET, PIH, PTB, low birth weight, PPH

Question 7

What is the preconception management of hypothyroidism

Answer 7

Titanite levothyroxine to be less than or equal to 2.5

When positive preg test increase the one of LevoTH by 25% - 30%

Question 8

How to dose levo in pregnancy is already on treatment

Answer 8

as soon as they have a positive pregnancy test: empirical increase in dose of
levothyroxine by approximately 25%–30%:

daily self-initiation of an empirical increase in the dose of levothyroxine by doubling the dose of levothyroxine on 2 days of each week

• or implementing a dose increment of:
-25μg per day for women taking 100μg or less levothyroxine daily
- 50μg per day for women taking greater than 100μg levothyroxine

Question 9

How to dose newly diagnosed hypothyroidism in pregnancy

Answer 9

Newly diagnosed OH: dose of 1.6μg per kg per day with repeat thyroid function tests
in 4 weeks

Question 10

How to monitor in pregnancy in on levoTH

Answer 10

pregnant women treated with levothyroxine: TSH and fT4 concentrations should be
checked every 4–6 weeks until 20 weeks of gestation then once again at 28 weeks of
gestation

,

Question 11

What is the aim of TSH in pregnancy if on LEVO

Answer 11

Aim TSH below 2.5mU/L while keeping fT4 within normal range for trimester

Question 12

What to do with Levo post partum

Answer 12

If on levo pre pregnancy - revert to preconception dose on levoTH @ 2 weeks postpartum

Question 13

Is woman was not taking levoTH pre pregnancy but started it in preg how to manage post delivery?

Answer 13

Stop levo and check thyroid 6 weeks post delivery

Question 14

Sub clinical hypothyroidism

Pre preggo treatment

And preggo treatment

Answer 14

• if TSH between upper limit of non preggo range and 10 with normal fT4
  TSH = high
  fT4= normal
  MC one!

Pre preggo- also if known to be TPOAb positive- consider treatment with levo for TSH less than or qual to 2.5

Treat with LevoTH if newsly diagnosed in 1st trimester

Treat with levo dose start at 1-1.2 micog per kg

Question 15

Isolated hypothyroxinaemia
What is the TSH and T4

Answer 15

TSH is normal
fT4 with low

1.3-8% prev - 2nd MC

Question 16

Gestational transient thyrotoxicosis

What is it and how to manage

Answer 16

New finding of suppressed serum TSH accompanied by an increased fT4 in pregnancy and other types of hyrotoxicosis

Should be distinguished from Graves with clinical features and measuring TSH receptor antibodies [TRAb) and fT3

Treat with symptomatic and supportive management only.

Recheck thyroid functions in 46 weeks after initial testing to ensure stability

Question 17

How much iodine do you need

Answer 17

Pre preg and in preg need 200 - 250 microg / day

Supplement in pregg with iodine rich food or 150ug/day

Question 18

Overt hyperthyroidism

Answer 18

TSH low
fT4 high

If left untreated increases risks, especially in preeclampsia, PTB, FGR, maternal heart failure

Question 19

Over hyperthyroidism how to treat?

Pre preggo and in preggo

Answer 19

Pre preggo: use Propulthiouracil over carbimazole

When preggo:
Consider discontinuing and anti thyroid drugs with close thyroid function monitoring, when a woman with history of hyperthyroidism, has been EUthyroid for six months or more, on a low-dose of an antithyroid drug

IF Drugs needed:
In early preg use PTU
If consieves on CMZ , switch to PTU asap before 10w

-During first half a pregnancy if on a drug needs thyroid bloods every 2 to 4 weeks
-after 20 weeks of pregnancy blood every 4-8 weeks is OK

Question 20

How to titrate anti-thyroid drugs and pregnancy

Answer 20

Titrate the drugs to target T4 concentrations in the upper half of the trimester and manufacturer specific pregnancy reference range

Question 21

Is sub clinical hyperthyroidism associated with anything in pregnancy?

Answer 21

TSH low
FT4 normal

It is not associated with adverse fetal or pregnancy outcomes and does not require treatment

Question 22

Is there too much iodine possible in diet

Answer 22

Do not exceed 500 microg

Question 23

What is the most common cause of iodine deficiency

Answer 23

Isolated Hypothyroxinaemia

Question 24

How can you treat Graves’ disease pre pregnancy

Answer 24

The option of definitive treatment with radioactive iodine or thyroidectomy should be discussed, especially in women with more severe disease.

Question 25

Post def treatment for graves how long to wait to get pregnant

Answer 25

6 months - wait then can start trying They should also have had serum fT4 within the reference range on two measurements 3 months apart pre pregnancy

Question 26

Is there any reason to delay conception post graves definitive treatment

Answer 26

Consider Delaying conception if there is a persistently raised TRAb level usually greater than 3 times the threshold for positivity - at 6 months post treatment

Question 27

Which drug for hyperthyroidism is best in preconception and in 1st trimester

Answer 27

PTU - Propylthiouracil

Question 28

Can you consider to stop antithyroid drugs pre-conception?

Answer 28

Yes once euthyroidism (TSH in the reference range) is maintained for at least 6 months on a low dose weighed against risks of a hyperthyroid flare

Question 29

What is the cause of post partum throiditis

Answer 29

symptoms during the first 3 months of thyrotixic symptoms usually due to POSTPARTUM thyrotoxicosis If thyrotoxicosis post 6 months usually caused by graves

Question 30

Another way to diagnose postpartum thyrotoxicosis is

Answer 30

Raised T4:T3 ratio Vs Graves= p=opthalmology, goiter, bruit, raised TRAb Postpartum thyrotoxicosis is the most common cause of thyrotoxicosis post preg

Question 31

Can you breastfeed with uptake of radioactive isotope

Answer 31

Can only breastfeed after discarding milk for 3 days after radioisotope investigation Uptake of radioactive isotope (Technetium [99mTc] or radioiodine [123I]) is increased in Graves' disease and low in PPT.

Question 32

What is the most sensitive test for detecting thyroid nodules

Answer 32

USS , , measuring their dimensions, identifying their content and evaluating any associated changes in the thyroid gland

Question 33

How to treat postpartum thyrotoxicosis

Answer 33

Antithyroid drugs are not indicated in the management of the thyrotoxic phase of PPT, only symptomatic ttt if needed “ ex: b-blockers ” Levothyroxine replacement is appropriate for women who are very symptomatic during the hypothyroid phase of PPT or actively trying to become pregnant >>> If levothyroxine is started in the hypothyroid phase, tapering off the dose may be attempted after 12 months, although this is not appropriate if women are actively trying for pregnancy and individualized treatment decisions should be taken

Question 34

Follow up post partum post Postpartum thyrotoxicosis

Answer 34

Thyroid function monitoring every 6 weeks until restoration of Euthyroidism • Following restoration of euthyroidism, monitor serum TSH annually as they continue to be at risk of developing permanent hypothyroidism There is insufficient evidence to recommend levothyroxine prophylaxis, or either iodine or selenium supplementation to prevent or treat PP

Question 35

What is PPT , postpartum thyrotoxicosis

Answer 35

is defined as the development of thyroid dys- function, excluding other thyroid diseases, within the first 12 months following a pregnancy in a previously euthyroid woman [203]. This is an autoimmune disorder asso- ciated with antibodies to TPO and thyroglobulin [204], caused by a reactivation of the immune system following the relative immune suppression during pregnancy PPT occurs in 5%–10% of unselected pregnancies [206]. Women with other autoimmune disorders are at increased risk, in par- ticular, those with type 1 diabetes mellitus [207], systemic lupus erythematosus [102] and a previous history of Graves' disease [208]. PPT may also occur in those with Hashimoto's thyroid- itis [209] or with a personal or family history of thyroid disease [205]. Overall, 30%–50% of women with positive TPOAb develop PPT with higher risk in those with higher TPO antibody concen- trations The classical form of PPT is triphasic with an initial thyrotoxic phase followed by a transient hypothyroid phase and then a return to euthyroidism. The clinical course is variable with 20%–40% of women exhibiting the classical form, 20%–30% developing only thyrotoxicosis and 40%–50% presenting with isolated hypothy- roidism [205, 210]. The thyrotoxic phase usually occurs between 2 and 6 months postpartum but may present up to 12 months fol- lowing birth. The hypothyroid phase typically presents between 3 and 12 months postpartum and results in permanent hypo- thyroidism in up to 50% [51, 211, 212]. Risk factors for perma- nent hypothyroidism include multiparity, higher concentrations of TPOAb, greater maternal age, more severe hypothyroidism, thyroid hypoechogenicity on ultrasound scanning and a history of pregnancy loss [51, 205, 213]. The risk of relapse of PPT with subse- quent pregnancies is as high as 70%, especially in TPOAb positive women PPT is characterised by evolving clinical features and biochemistry indicative of thyroid dysfunction. Increased TRAb and diffuse uptake of isotopes are consistent with Graves' disease