The document discusses the management of thyroid disorders during pregnancy, highlighting the physiological changes, risks associated with thyroid dysfunction, and management strategies. It emphasizes the importance of addressing both hyperthyroidism and hypothyroidism, as well as postpartum thyroid disorders to prevent complications for both mother and fetus. Recommendations also include iodine supplementation and monitoring thyroid function in women planning for or during pregnancy to ensure optimal outcomes.

1. Thyroid disorders in
Pregnancy
Dr Shahjada Selim
Associate Professor, Department Of Endocrinology, BSMMU
Visiting Professor In Endocrinology, Texila American University, USA
Website: http://shahjadaselim.com

2. Outline of presentation
Physiologic Changes in Thyroid Function During
Pregnancy
Why thyroid dysfunction need to be focused
How to manage hyperthyroidism in pregnancy
Special attention on hypothyroidism in pregnancy
Why attention to be given in postpartum stage
Postpartum thyroid disorders
Conclusion

4. Modulation of maternal immune surveillance system
Progesterone- Decreases reactivity of humoral and cellular
arms of the immune system
Oestrogen- exerts opposite effect
As P/Oe increases, immune system dampened
All lead to clinical improvement of autoimmune diseases
After pregnancy: Rapid reduction immune suppressor
function
Re-establishment and exacerbation of these conditions
Autoimmune Thyroid disease and Pregnancy

5. Miscarriage in Women with +ve TPO Antibodies
15 original studies
13 (87%) +ve assoc
2 (13%) no assoc
Meta analysis case control and longitudinal studies [Prummel and Wiersinga 2004]
1. ? AITD a marker only
2. ? Reduced thyroid functional reserve during pregnancy
3. ? AITD delay conception.. effect of age on pregnancy loss
Poppe & Glinoer 2003
Stagnaro-Green & Glinoer 2004
RR of 3 in women with AITD

6. Pregnancy, Thyroid Antibodies and Outcome
• Euthyroid women with Abs tend to be older when
first pregnant
• They have reduced thyroid functional reserve (TSH
higher in Ab+ve women)
• Increased risk of obstetric complications
• T4 intervention reduces chance of miscarriage and
premature delivery
• ? Screening strategy in early pregnancy
adapted from Glinoer 2006 JCEM 91:2500-2502

7. Impact of Iodine Deficiency
Iodine is required for neural development of fetal brain-
cretinism, intellectual impairment ,deaf- mutism, motor rigidity
Universal salt iodination most cost effective
US Institute of Medicine : Daily supplement 150µgm/d planning
for pregnancy, 220 µgm/d in pregnancy,290 µgm/d in breast
feeding state
WHO 250 µgm/d in pregnancy and lactation period

8. Bangladesh achieved significant success over the years, with
80.3% households consuming iodized salt (57% consuming
adequately iodized salt at ≥15 ppm).
Recent surveys indicate that there is stagnation in the progress
towards USI, and the adequately iodized salt coverage is
hovering around the 50% mark.
Considerable efforts are required to reach the USI target of
>90% coverage.
Pandav CS et al 2016. IDD Newsletter
Key recommendations were shared:
1. Effective and transparent governance
2. Effective co-ordination between USI stakeholders
3. Supply of adequately iodized salt
4. Regular and robust outcome assessment
5. Demand for adequately iodized salt
Improving USI strategy in Bangladesh

9. • Fetal thyroid development does not begin until 10 to 12 wks,
and then continues until term.
• The fetus’s need for thyroxine starts to increase as early as 5
wks of gestation. And little hormone is produced until 18-20
weeks then fetal hormone increases gradually.
• Synthesis of thyroid hormone starts after 11-12 wks gestation
• During early gestation: the fetus receives thyroid hormone from
the mother exclusively before 12 wks and partially thereafter for
normal fetal neurological development. Maternal T4 crosses the
placenta actively, the only hormone that does so.
Fetal thyroid function
• Preconception optimization of T4 therapy is
important
• Maternal hypothyroidism could be detrimental
to fetal development if not detected and
corrected very early in gestation.

10. Conditions Maternal Fetal
Hypothyroidism Anemia Congenital malformations
Gestational HTN Cretinism
Preeclampsia Preterm Delivery
Increased placental weight Low birth weight
Increased CS Spontaneous abortion
Post partum HMG Fetal distress
CCF Neuromotor-cognitive
Hyperthyroidism Heart failure Goiter
Placental abruption IUGR
Preeclampsia Low birth weight
pre term delivery Small for gestational age
GDM Still birth
Accelerated HTN Pre term delivery
Thyroid storm Thyroid dysfunction
Maternal and fetal complications associated with thyroid
dysfunctions with pregnancy

11. Current thyroid therapy or H/o Hypo or hyper Previous neck surgery
Previously euthyroid with antibodies Goiter
Family history of thyroid disorders History of other
Autoimmunity
Neck radiation Repeated pregnancy loss
History of previous postpartum disorders Type 1 DM
Infertility Obesity
Above the of 30 yrs Drug –amioderone,lithium
When to screen
• Universal screening or screening of high risk woman is to be
practiced is not yet settled. Majority is of the opinion, that evidence
is insufficient in favor of routine screening.
• Screening should be with at least TSH and if necessary fT3 and fT4
may be tested.
• Aggressive detection of women at high risk for thyroid dysfunction
in any lifetime particularly in reproductive age, must before planning
for conception

12. Thyroid Problems encountered in Pregnancy
Is it before conception –assess and ensure adequate level
assigned for conception for good outcomes, preconception
counseling
Functional disorders :
Hyperfunction
Hypofunction
Euthyroid
Structural disorders :
Diffuse enlargement
Nodular-single nodule or
multinodular
Detected during Gestation
Post partum period

13. Thyroid Disease in Pregnancy-
Epidemiology
Thyroid disorders- 15.3%
• Autoantibodies 18.6%
• Hypothyroidism 7.2%
1. Subclinical 6.8%
2. Overt 0.4%
• Hyperthyroidism 4.1%
1. Subclinical 3.6%
2. Overt 0.5%
Casey BM, Leveno KJ Thyroid disease in pregnancy. Obstet Gynecol 2006;108:1283–92.

14. Thyroid Tests
Thyroid Hormones – TT3,TT4, FT3, FT4, FT4I,TSH
Thyroid antibodies - TPOAb,TgAb,
TRAb (TSI,TBII)
USG of thyroid
CBC ESR
RAIU and scan –not recommended
For suspected nodule FNAC

15. Hyperthyroidism in pregnancy
• About 0.2% of pregnancies
• Prevalence 0.1% to 2.0% with 95% Graves’ disease
– Single toxic adenoma, multinodular toxic goiter, and
subacute thyroiditis
– Gestational trophoblastic disease, viral thyroiditis and
tumors of the pituitary gland or ovary (struma ovarii)
• TSH is suppressed usually <0.01mU/L and FT4 and FTI,FT3 are
increased.
• The RTIU that normally is decreased in pregnancy is increased
in hyperthyroidism.

16. Causes of hyperthyroidism in pregnancy
Grave’s Disease
Gestational Thyrotoxicosis
Hydatidiform mole
Silent Thyroiditis
Multinodular toxic goiter
Toxic adenoma
Subacute thyroiditis
Iatrogenic hyperthyroidismIodine induced
hyperthyroidism

17. Hyperthyroidism and pregnancy
• May be difficult to determine the cause
– thyroid radionuclide imaging is contraindicated in
pregnant women.
• Measurement of thyrotropin receptor antibody
(thyroid stimulating immunoglobulins)  Graves'
disease during pregnancy
• Transient hyperthyroidism in hyperemesis gravidarum
and gestational transient thyrotoxicity (GTT)

18. Transient hyperthyroidism during pregnancy &
gestational transient thyrotoxicity (GTT)
• Hyperemesis gravidarum : usually in 1st trimester
– severe nausea and vomiting leading to a 5% loss of
body weight, dehydration, electrolyte imbalance and
ketosis.
– absence of goiter and ophthalmopathy, and absence
of the common symptoms and signs of
hyperthyroidism
– higher serum hCG and estradiol concentrations
– 60% have a subnormal serum TSH level (<0.4 mU/L),
50% have an elevated serum free T4 concentration

19. Transient hyperthyroidism during pregnancy &
gestational transient thyrotoxicity (GTT)
– Severity positively correlated with maternal free T4
levels but not to thyroid function.
• <15% elevated FT3 or FT3 index clinically
distinguished test to differentiate from Graves
– believed to be related to hCG stimulation of the
thyroid gland
– Normalization of T4 levels by mid-gestation. If
normalization does not occur - think other causes
–Treatment is supportive care

20. Trophoblastic hyperthyroidism
• Hydatidiform mole (molar pregnancy) & choriocarcinoma.
– high serum hCG concentrations and abnormal hCG
isoforms
• 55 to 60 percent had clinically evident hyperthyroidism
• Normal thyroid gland and few symptoms of thyroid hormone
excess.
• Some findings of hyperthyroidism and a diffuse goiter
– ophthalmopathy is not present
• Nausea and vomiting may predominate

21. How to follow up?
• Repeat thyroid function tests after 20th week
• If persistent hyperemesis and elevated thyroid
hormones and suppressed TSH after 20 weeks of
gestation consider antithyroid treatment as this may
be mild Grave’s disease.

22. Subclinical hyperthyroidism
• Low TSH and normal free T4.
• Associated with osteoporosis, cardiovascular
morbidity, and progression to overt thyrotoxicosis
and thyroid failure.
• Not associated with adverse pregnancy outcomes
• Does not warrant treatment.

23. Graves’ disease
• About 95% of thyrotoxicosis during pregnancy.
• Activity level fluctuate during gestation, with
– exacerbation during the first trimester
– gradual improvement during the later half.
– exacerbation shortly after delivery
• Clinical scenarios.
– stable Graves’ disease receiving thionamide therapy with
exacerbation during early pregnancy.
– in remission with a relapse of disease.
– without prior history diagnosed with Graves’ disease de
novo during pregnancy.

24. Graves’ disease
• Diagnosis
– difficult :hypermetabolic symptoms in normal pregnancy
– thyroid examination: goiter (with or without bruit)
– suppressed serum TSH level and usually elevated free and
total T4 serum concentrations.
– TSH receptor antibodies (Very helful)
• Complications related to the duration and control of
maternal hyperthyroidism
• Autoantibodies mimic TSH can cross the placenta and cause
neonatal Graves’ disease

25. Diagnosis of Grave’s
• Symptoms of hypermetabolic state
• Sometimes goiter with bruit
• Eye signs
• Elevated free T3 and freeT4
• Suppressed TSH
• RAIU elevated(not done in pregnant)
• Elevated TgAb and TPOAb
• TRAb positive to differentiate from other
hyperthyroid state

26. Graves’ disease
• Pregnancy outcome
• Preterm labor
– untreated (88%)/partially treated (25%) /adequately treated
(8%)
• Preeclampsia
– untreated twice
• Stillbirth
– untreated (50%) /partially treated (16%) /adequately treated
(0%)
• Small for gestational age
• congenital malformations unrelated to thionamide therapy
• Mother may have thyroid-stimulating hormone-binding
inhibitory immunoglobulin (TBII),
– cause transient neonatal hypothyroidism
– fetal bradycardia, goiter, and growth restriction

27. Guidelines for clinical management of maternal
hyperthyroidism during pregnancy
• 1. Use the lowest dosage of thionamide (preferably PTU) to
maintain maternal FT4 concentrations at the upper level of
normal or slightly elevated range of upper limit for non-
pregnancy reference range.
– Normal range of total T4 during pregnancy is estimated to
be 1.5 times the nonpregnant state
• 2. Monitor maternal total T4 / FT4 serum concentration every
2–4 weeks, and titrate thionamide as necessary.
– Monitoring serum TSH may become useful later.
Shane O. LeBeau, tetab Clin N Am 35 (2006) 117–136

28. Guidelines for clinical management of maternal
hyperthyroidism during pregnancy
• 5. Consider thyroidectomy if persistently high doses of
thionamide (PTU > 600 mg/d or MMI > 40 mg/d) are
required, or if the patient cannot tolerate thionamide
therapy.
• 6. β-Adrenergic blocking agents and low doses of iodine may
be used perioperatively to control hyperthyroid state.
• 7. Check fetal cord blood at delivery for TSH and T4.

29. Which ATD is best?
PTU favored up to 12-16 weeks because:
• PTU is heavily protein bound and believed to cross placenta
less, so congenital malformation are less
• MMI has been associated with aplasia cutis a congenital
scalp defect, MMI embryopathy-dysmorphic facies, choanal
and esophageal atresia ,abdominal wall defect-umbilicocele
• PTU is hepato toxic-withdraw after first trimester, monitor
liver function test before starting and 2-4 weeks interval

30. Propylthiouracil (PTU) and Methimazole(MMI)
• Both cross the placenta with equal transfer kinetics.
• Both can cause fetal goiter and hypothyroidism, usually
mild and transient & dose-dependent
• median time to normalization of maternal thyroid
function
– 7 weeks with PTU and 8 weeks with MMI
Thionamides

31. • PTU more highly bound to albumin
– theorize that MMI crosses the placenta in higher
concentrations
– Typical dose of MMI-5-30mg/D,CM-10-40mg/D,PTU-100-
600mg/D(MMI to PTU is 1;20
– Start with PTU or switch to PTU when pregnancy detected
through 16 weeks, then shift to MMI in 1:20 ratio
– Monitor TSH,FT4 every 4 weeks interval, keep on lowest
effective dose
– Monitor TRAb if high in early pregnancy, repeat at 18- 22
weeks if remain high check at 30-34 weeks. high TRAb predict
neonatal hyperthyroidism
Thionamides

32. • Maternal : rash
• Low thyroid function at birth ½ neonates whose mothers
received PTU or MMI and had serum T4 concentrations
within the normal (non-pregnant) range
– normal IQ scores
• Graves’ disease may ameliorate
– thionamide discontinued in 30% during the final weeks
– fall in serum TSH receptor-stimulating antibody
concentrations and a rise in TSH receptor-blocking
antibodies.
• Graves' hyperthyroidism can worsen postpartum
• Do not recommend the use of T4 with thionamide therapy
during pregnancy.

33. β-Adrenergic blockers
• weaned as soon as the hyperthyroidism is controlled
• occasional cases of neonatal growth restriction, hypoglycemia,
respiratory depression, and bradycardia
• increased frequency of first-trimester miscarriages
• avoiding in the first trimester
Iodides
• past reports of neonatal hypothyroidism after exposure to
iodine
• low-dose potassium iodide may be considered
– Preparation for thyroidectomy
– thionamide-intolerant patients refusing surgery.

34. Subtotal thyroidectomy :
– persistently high dosages of thionamides (PTU > 600 mg/d,
MMI > 40 mg/d) are required to control maternal disease
– allergic or intolerant of both thionamides
– noncompliant with medical therapy
– Huge goitre with compressive symptoms
• Second trimester, before gestational week 24
• Prepared with a β-adrenergic blocking agent and a 10- to 14-
day course of potassium iodide
Surgery

35. Radioactive iodine therapy
• contraindicated
• fetal thyroid gland begins to concentrate iodine after
gestational week 10, Fetal thyroid tissue is present by 10 to 12
weeks
– predisposing to congenital hypothyroidism
Nursing
• Breast feeding in mothers taking PTU or MMI is safe
• Thyroid function in newborn infants is unaffected
• PTU is preferred because it is less concentrated in breast milk

36. Sub clinical hypothyroid in pregnancy
Subclinical hypothyroidism • Elevated serum TSH and
normal FT4 • Biochemical thyroid hormone deficiency
Subclinical Hypothyroidism • L-Thyroxine therapy for all
pregnant women with subclinical hypothyroidism
• Initiate dose according to TSH Levels AIM: Step up and
then Down
• Check TSH level and FT4 after 2-4weeks and then TSH - 4-
6 weeks or every trimester
• Dose to be reduced gradually after delivery
• Repeat TSH at 6 weeks postpartum

37. Sub clinical hypothyroid in pregnancy: outcomes
Sub clinical hypothyroid may impact fertility-pregnancy loss,
premature delivery, placental abruption, neuro-cognitive
effects in offspring's
Even anti-thyroid positive but euthyroid may influence follicular
development
Evolution of thyroid function should be done seeking care for
fertility
In sub clinical hypothyroid for natural pregnancy. But data is
insufficient for replacement but needed to reduce the progress ,
More applicable in ART as TSH <2.5mU/L have higher pregnancy
success than TSH >2.5mU/L

38. Sub clinical hypothyroid in pregnancy-Recommendations
Pregnant women with TSH >2.5mU/L should be evaluated for TPO anti-bodies
Subclinical hypothyroidism in pregnancy should be approached
- Thyroxin replacement in TPO positive + TSH > pregnancy specific range
- TPO negative with TSH >10.0mU/L
- TPO positive with TSH >2.5mU/L and < upper limit of pregnancy specific range
- TPO negative with TSH greater than pregnancy specific but below 10mU/L
- TPO negative with within pregnancy specific or <4.0mU/L if unavailable
Reasonable target for replacement: in the lower half of trimester specific range
or below <2.5mU/L
Euthyroid patients who antibodies positive, post hemi-thyroidectomy or treated
with radio iodine have increased propensity for hypothyroid in gestation, so
monitor regularly ,every 4 weeks up to mid gestation

39. Hypothyroid at preconception
Treated hypothyroid women receiving thyroxine seeking
for conception should be counseled to optimize thyroid
parameter <2.5mU/L, reasonably <1.5( between lower limit
and 2.5mU/L -as increased likely hood of increased demand)
Contact immediately with care giver as soon as confirm after
taking 2 additional dose weekly of current daily dose.

40. Hypothyroidism
•Incidence: Much more common in women than men
Common in those with family history
•Overt hypothyroidism: 0.3% - 2.5% of pregnancies active
intervention is required to prevent serious damage to the
fetus.
•Subclinical disease: 2% to 3% of pregnancies Current
research indicates that intervention may be indicated.

41. Hypothyroidism
•Difficulty in conceiving
•Majority on thyroxine prior to pregnancy
•Incidence is 9/1000 pregnancy
•Risks: fetal loss: abortion, still birth, premature
labour
•In the newborn, congenital cretinism as a result of
congenital hypothyroidism

42. Hypothyroidism in pregnancy
• Elevated serum TSH concentration:2.5% of pregnancies
• Causes:
In iodine-sufficient environment
– Hashimoto’s thyroiditis
 Prior radioactive iodine treatment
 surgical ablation of Graves’ disease
 Less common causes: overtreatment of hyperthyroidism with
thionamides, transient hypothyroidism owing to postpartum
thyroiditis, medications that alter the absorption or
metabolism of levothyroxine, and pituitary/hypothalamic
disease (Sheehan, hypophysitis, pituitary surgery)
 Drugs-lithium, Somatostatin, steroid, Dopamin agonists,
Sucralfate, cholestyrimine, ferrous sulfate)

43. Guidelines for clinical management of maternal
hypothyroidism during pregnancy
1. Check serum TSH level as soon as pregnancy is confirmed.
2. For newly diagnosed hypothyroid women, initial levothyroxine
dosage is based on severity of hypothyroidism. For overt
hypothyroidism, administer 2 mcg/kg/d. If TSH is < 10 mU/L,
initial dose of 0.1 mg/d may be sufficient.
3. For previously diagnosed hypothyroid women, monitor serum
TSH every 3–4 weeks during first half of pregnancy and every 6
weeks thereafter.
4. Adjust levothyroxine dosage to maintain serum TSH ≤ 2.5 mU/L.
5. Monitor serum TSH and total T4 levels 3–4 weeks after every
dosage adjustment. When levothyroxine dosage achieves
equilibrium, resume monitoring TSH alone
Shane O. LeBeau, Endocrinol Metab Clin N Am35 (2006) 117–136

44. Treatment
6. Levothyroxine ingestion should be separated from
prenatal vitamins containing iron, iron and calcium
supplements, and soy products by at least 4 hours to
ensure adequate absorption.
7. After delivery, reduce levothyroxine to prepregnancy
dosage, and check serum TSH in 6 weeks
• Patients who were on thyroxine therapy before pregnancy
should increase the dose by 30% once pregnancy is
confirmed (Bombrys et al, 2008)

45. Postpartum Thyroid Disease
• Postpartum thyroiditis
– documenting abnormal TSH (elevated or suppressed) levels
during the first year postpartum in the absence of positive
TSI or a toxic nodule in eu-thyroid pre-pregnancy
– Presence of autoimmunity antibodies positive
– hypo- or hyperthyroidism or eu-thyroid
– classic presentation :
– transient hyperthyroid phase that occurs 6 weeks to 6 months
postpartum
– followed by a hypothyroid phase that lasts for up to 1 year
postpartum, 10-20% remained permanent hypothyroidism

46. Patterns of Thyroid Function Post Partum
From AMINO

49. Risk Factors for Postpartum Disease
• Previous episode of PPTD
• History of AITD (eg Hashimoto)
• Diabetes Mellitus Type I
• Recurrent miscarriages
• Goitre
• Family History of AITD

50. Overt hypothyroidism
TPOAb
Time
0
100
Thyroid
reserve
%
Pregnancy
Immunogenetic background [eg HLA + other genes]
Overt hypothyroidism
Subclinical hypothyroidism
Postpartum
Development of Postpartum Thyroid Dysfunction
Cellular immunity
? Fetal microchimerism

51. Postpartum thyroiditis
• Can also occur after spontaneous or induced abortion
• More in other autoimmune disorders
– higher, up to 25 percent, in women with type 1 diabetes
mellitus
– in women with positive antithyroid antibodies (normal
thyroid function)
– higher antibodies titre in 1st trimestor -higher PPT
– PPT in previous pregnancy

52. Antithyroids : no role. For symptoms –beta blocker
Hypothyroid : may require treatment and some
significant rate of residual hypothyroidism, monitor 6-8 weeks
interval, after 1 year withdrawal is attempted gradually if not
seeking next conception
Recommend: maintain thyroxine until childbearing is
complete, with an attempt to wean off medication 1 year
after the last delivery
Treatment

53. Postpartum Graves’ disease
• 60% Graves’ disease in the reproductive years : postpartum
onset
• euthyroid patients with Graves’ disease with TSI
– increased risk of developing recurrent Graves’ disease if antithyroid
medication was withheld
• TSIs differentiate postpartum Graves’ disease from
postpartum thyroiditis with a hyperthyroid component.

54. Preconception counseling
Hypothyroid mothers on replacement-optimize replacement
Teach how to accelerate the dose as soon as confirm conception
-empirically 2 extra dose per week
How to follow up during gestation and afterword
Mother with antibody screening should be done before going
to conceive
 Hyperthyroid mother-stable with ATD –minimum
dose
 Explain the consequences of disease itself and ATD
 How to use ATD, which drug and when
 How to follow
 What to look for fetus and baby

55. • Uncontrolled or inadequate control of thyroid
dysfunction in pregnancy is associated with adverse fetal
and maternal Outcomes
• Hyperthyroidism in pregnancy requires careful control of
maternal disease whilst avoiding fetal hypothyroidism
• Propylthiouracil is the preferred antithyroid drug in
pregnancy although methimazole can be used where
propylthiouracil is unavailable
• Synthetic levothyroxine is the treatment of choice in
hypothyroidism
Conclusions

56. • Patients with pre-existing hypothyroidism usually require
an increase in thyroxine dose in pregnancy
• Most patients with postpartum thyroiditis will
require treatment during the hypothyroid phase
• Long-term follow-up of patients with this syndrome
is essential owing to the risk of permanent
hypothyroidism
• Subclinical hypothyroidism in pregnancy requires
replacement treatment
• Excellent maternal and fetal outcomes can be achieved
with appropriate management of thyroid dysfunction in
pregnancy
Conclusions