Thyroid Disorders in Pregnancy

Question 1

Answer 1

case 2 has evident hyperthyroidism, but TSH is pretty low in the case 1 as well, indicating that it might have a subclinical picture

Question 2

clinical features of hyperthyroidism common to pregnancy

Answer 2

1. 1. heat intolerance
2. 2. tachycardia
3. wide pulse pressure
4. flow murmur
5. radiant heat from hands
6. goiter– in iodine deficient areas

Question 3

Changes in thyroid physilogy in pregnancy:

• HCG stimulates ___ receptor
• HCG peaks at end of ___ trimester

- 20% of pregnant women have TSH below nonppregnant TSH reference range from 8-14 weeks gestation, but free T4 and T3 is normal.

Answer 3

• HCG stimulates TSH receptor
• HCG peaks at end of 1st trimester

- 20% of pregnant women TSH below nonppregnant TSH reference range from 8-14 weeks gestation, but free T4 and T3 is normal.

Question 4

how does TSH level and free T4 levels change during pregnancy

Answer 4

TSH: first trimester: reduced TSH at 7-14 weeks), then it rreturns to baseline in third trimester.

• free T4 decreases is in the second and third trimesters

3) 20% pregnant women TSH below nonpregnant TSH
reference range from 8-14 wks gestation but Free T4 and
Free T3 normal

Question 5

outline how TSH levels normal range change depending on gestational weeks

Answer 5

Question 6

in pregnancy, thyroid binding globulin concentration ____. Why?

Answer 6

increases by 2-3 times. Estrogens stimulate expression of TBG in liver, and the normal rise in estrogen during pregnancy induces roughly a doubling in serum TBG concentratrations.

Question 7

General outline when first thinking about thyroid issues in pregnancy

Answer 7

1. check for goiter
2. use gestational age specific TSH reference range
3. look at free Y4 and T3
4. clinical follow up and repeat TSH 4 weeks later.

Question 8

most common etiology of hyperthyroidism in pregnancy

Answer 8

85-90% of casese of hyperthyroidism in pregnancy is Graves disease

• other etiologies include toxic MN goiter, subacute thyroiditis, toxic adenoma, gestational trophoblastic disease

Question 9

causes of Transient Hyperthyroxinemia of Pregnancy

Answer 9

Question 10

hyperthyroidism and pregnancy general diagnosis

Answer 10

decreased TSH
increased free T4, free t3,

goiter

Question 11

5 risks of untreated hyperthyroidism in pregnancy

Answer 11

1. miscarriage
2. preterm delivery
3. lpw bith weight
4. pre-exlampsia
5. thyroid storm

Question 12

T/f the first step of manageing hyperthyroidism in pregnancy is radioiodine

Answer 12

false. radioiodine is contraindicated

Question 13

Which antithyroid medication is preferred to use in hypertension of pregnancy? compare the two most common classes

Answer 13

Propylthiouracil (PTU) preferred over Methimazole (<16
weeks gestation)

Question 14

outline the birthdefects seen in the use of methimazole anti-thyroid meds (Methimazole Embryopathy)

Answer 14

choanal atresia common

Question 15

general management of hyperthyroidism in pregnancy if you can’t use radioiodine

Answer 15

4) Render pt euthyroid with low dose antithyroid
medication (PTU preferred until 16 wks gestation)
•

5) Monitor TSH, Free T4 every 1 to 4 wks to titrate
antithyroid medication

• 6)Keep Maternal freeT4 high trimester specific normal

Question 16

note

Question 17

t/f anti-thyroid drugs are safe for breastfeeding

Answer 17

true

Question 18

true false: radioiodine remains contraindicated of breasfeeding

Answer 18

true

Question 19

t/f post partum relapse of hyperthryoidism is common

Answer 19

true

Question 20

if someone is hyperthyroid before conception, what should you do?

Answer 20

fix prior to pregnancy! use I131 plus 6 month contraception while fixing it. consider surgery

Question 21

note; this demonstrates that PTU is safer than MMZ as an antithyroid drug because it is less liekly to go to the fetus. it also shows the iodine is contraindicated because it fully goes to the fetus

Question 22

outline the relationship between maternal Graves disease and fetal risk of hyperthyroidism

Answer 22

the rate is 1-3%.

• if the TSH receptor antibodies are over 8 times greater than normal, it predicts higher risk for fetal/neonatal hyperthyroidism

Question 23

lab values for OVERT HYPOthyroidism in pregnanyc

Answer 23

TSH >10mU/L

low free T4

Question 24

Women at risk for hypothyroidism in pregnancy

Answer 24

1. ones with overt hypothyroidism
2. women on thyroid replacement
3. not women with minor TSH elevatois (subclinical hypothyroidism)

Question 25

consequences of untreated overt maternal hypothyroidism

Answer 25

1. fetal loss 2. hypertension 3 .placental abruption 4. post partum hemorrahe 5. impaired neurodevelopment in child in overt hypothyroidism

Question 26

Changes in Thyroid Physiology in Pregnancy • __ \_\_ __ (TBG) increases • 20 - 40% **\_\_** in maternal __ production required to saturated the increase binding sites

Answer 26

Changes in Thyroid Physiology in Pregnancy • **Thyroid binding globulin (TBG)** increases • 20 - 40% **increase** in maternal **T4** production required to saturated the increase binding sites

Question 27

* *Reminders for Childbearing age women on thyroid replacement** 1) Separate L **\_\_** from **\_\_** or **\_\_** by at least 2 hours 2) Preconception: • TSH \< **1.2** mIU/L monitor **\_\_\_** • TSH \>**1.2** mIU/L **\_\_** by **\_\_\_ tablet/wk once pregnant** 3) when Postpartum return to prepregnancy dose

Answer 27

* *Reminders for Childbearing age women on thyroid replacement** 1) Separate L **thyroxine** from **iron** or **calcium** by at least 2 hours 2) Preconception • TSH \< **1.2** mIU/L monitor **TSH** • TSH \>**1.2** mIU/L **Increase** by **2 tablet/wk once pregnant** 3) Postpartum return to prepregnancy dose

Question 28

How frequently do you monitor TSH in pregnancy and after

Answer 28

\<20 weeks; q 4 weeks until stable then: Q trimester (once a trimester) 6-8 weeks postpartum

Question 29

Thyroid Supplementation During Pregnancy • Who to treat?

Answer 29

Women on **Thyroid Replacement Preconception** need monitoring **+/- dosage adjustment t**o avoid overt hypothyroidism in pregnancy OR • TSH \> 10mU/L discovered **in** pregnancy

Question 30

T/F You should give thyroid supplementation fo those with TSH\<5 in pregnancy

Answer 30

false. Who not to treat? • TSH \< 5mU/L discovered in pregnancy • Normal TSH with positive antibodies

Question 31

T/F you should treat women with anti-thyroid antibodies but normal TSH in pregnancy

Answer 31

false Who not to treat? • TSH \< 5mU/L discovered in pregnancy • Normal TSH with positive antibodies

Question 32

Question 33

If you give too much thyroid supplementation,it can cause TSH suppression which is also bad. Who is at risk of TSH suppression?

Answer 33

Post hoc analysis to explore factors associated with TSH suppression \<0.1. mIU/L during pregnancy **1) preconception** TSH \<1.50mIU/L **2) levothyroxine** dose greater than 100 mcg/day

Question 34

how do TSH levels change in pregnancy?

Answer 34

in the first trimester, TSH decreases, and then return back to normal in the second and third trimesters

Question 35

Outline the scheme of TSH management/checking in pregnancy in a patient with NO HISTORY OF THYROID DYSFUCNTION

Answer 35

Question 36

T/F babies born to mothers with subclinical hypothyroidism have been shown to have reduced IQ

Answer 36

false. even when thyroxine was started, there was no difference.

Question 37

T/F: giving Levothyroxine preconception for women with Positive Thyroid Antibodies have been shown to improve pregnancy outcomes

Answer 37

false.

Question 38

note: key messages about thyroid replacement in pregnancy

Answer 38

Question 39

That is the Etiology of her Hyperthyroid State? A) Graves’ Disease B) Postpartum thyroiditis C) Toxic thyroid adenoma D) All of the above

Answer 39

could be anything but **graves** is the most common

Question 40

Post partum thyroiditis: 5-10% of women postpartum get thyroiditis - women with ____ are 25% more likely

Answer 40

TYPE 1 DM

Question 41

Etiologies of post partum thyroiditis

Answer 41

Etiology • immune mediated • thyroid antibodies • lymphocytic infiltration • destructive thyroiditis

Question 42

Clinical features of thyroid gland is woman with PPThyroiditis? painful? enlarged? soft or firm?

Answer 42

NON painful NON tender slightly enlarged firm

Question 43

natural history of post partum thyroiditis

Answer 43

* Transient Hyperthyroidism 2-4 months postpartum * Resolution * Hypothyroidism 5-8 months postpartum * Hypothyroidism permanent - 25% **• 70% recurrence in subsequent pregnancy** **• 50% permanent hypothyroidism in 7 years**

Question 44

ESR, TSG, I131 levels in someone with post partum thyroiditis

Answer 44

ESR; normal TSH; increasd, normal, decreased lol could be anything I131 : decreased uptake because they are releasing their contents

Question 45

post partum thyroiditis management in the hyperthyroid phase

Answer 45

SO NOT GIVE ANTITHYROID MEDS, but consider beta blockers

Question 46

post partum thyroiditis management of the hypothyroid phase

Answer 46

consider low dose thyroxine replacement, low dose and under a 1 year duration

Question 47

T/F: it is good to use desiccated thyroid (med with T4 and T3) during management of hypothyroidism in pregnancy

Answer 47

FALSE. AVOID ANY t3 contianing preparation during pregnancy.