Thyroid disease in pregnancy

1. Thyroid disease in pregnancy
Dr. Hem Nath Subedi, Resident
OBGYN
COMS TH , BHARATPUR, NEPAL

2. Objectives
• To explain anatomic structure and physiologic
function of the gland.
• To explain role of thyroid hormone in
Pregnancy
• To Explain disease entity of thyroid in
pregnant woman.
• To give knowledge to participants about
clinical features and management regarding
thyroid disease.

3. Contents
• Anatomy
• Physiology
• Changes in thyroid physiology in pregnancy
• Hyperthyroidism in pregnancy
• Hypothyroidism in pregnancy
• Management
• Screening in pregnant women
• Postpartum thyroiditis
• Thyroid nodules and pregnancy

4. Anatomy
• The thyroid gland is
anterior in the neck below
and lateral to the thyroid
cartilage.
• It consists of
– Two lateral lobes
– Isthmus
Richard F .Thyroid anatomy In GRAY’S Anatomy, third edition , Elseveir, uk , 2015

7. Histology
Kim E. Thyroid Physiology In Ganong’ Review of Medica Physiology, 24th edition, New York, Mac

8. Physiology
Kim E. Thyroid Physiology In Ganong’ Review of Medica Physiology, 24th edition, New York, Mac

9. Iodine Metabolism
Kim E. Thyroid Physiology In Ganong’ Review of Medica Physiology, 24th edition, New York, Mac

10. Thyroid hormone biosynthesis
Kim E. Thyroid Physiology In Ganong’ Review of Medica Physiology, 24th edition, New York, Mac

12. Kim E. Thyroid Physiology In Ganong’ Review of Medica Physiology, 24th edition, New York, Mac

13. Thyroid hormone in circulation
Kim E. Thyroid Physiology In Ganong’ Review of Medica Physiology, 24th edition, New York, Mac

14. Regulation of thyroid hormone secretion
Kim E. Thyroid Physiology In Ganong’ Review of Medica Physiology, 24th edition, New York, Mac

15. Changes in Pregnancy
• Physiological changes of pregnancy cause the thyroid
gland to increase production of thyroid hormones by
40 to 100 percent to meet maternal and fetal needs.
• mean thyroid volume increased from 12 mL in the first
trimester to 15 mL at delivery pregnancy-induced
changes.
• TRH levels are not increased during normal pregnancy.
• Due to beta-hcg, initially TSH level decrease in
pregnancy, which give false report of subclinical
hypothyroidism.
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

16. Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

17. Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

18. Hyperthyroidism
• Hyperthyroidism affects 0.2 % of pregnant
women and 95% of these will have diagnosis of
Grave’s disease .
• The incidence of thyrotoxicosis or
hyperthyroidism in pregnancy is varied and
complicates between 2 and 17 per 1000 births
when gestational-age appropriate TSH threshold
values are used.
• In Nepal incidence of hyperthyroidism is 1.59%.

19. Graves disease
• Graves' disease, also known as toxic diffuse
goiter is an autoimmune disease that affects
the thyroid.
• A long-acting thyroid stimulator (LATS),
distinct from pituitary thyrotropin (TSH), is
found in the serum of some patients with
Graves' disease.
• Graves' hyperthyroidism was found to contain
a long-acting thyroid stimulator (LATS)

20. Incidence
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

21. Possible causes of hyperthyroidism
• Graves Disease
• Toxic Multinodular Goiter
• Toxic nodule/adenoma
• Subacute thyroiditis
• Acute thyroiditis
• Iordine treatment
• Amiodarone therapy
• Lithum therapy
• Hyperfunctioning ovarian teratoma
• TSH producing adenoma
• hCG producing tumor
• Thyroid carcinoma
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth
edition, uk , elsevier, 2006 pp 813-829.

22. Clinical features
• Suggestive findings include tachycardia that
exceeds that usually seen with normal
pregnancy, thyromegaly, exophthalmos, and
failure to gain weight despite adequate food
intake.
• Diagnosing hyperthyroidism in early
pregnancy may be difficult.
• Some time associated with Hyperemesis.
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth
edition, uk , elsevier, 2006 pp 813-829.

23. Maternal effect
• Prepregnacy
– Infertility
• 1st trimester
– Miscarriage
– Hyperemesis
• Second and third trimester
– Heart failure
– Preeclampsia
– Adverse perinatal outcome- perinatal mortality rate is
6- 12%.(IUGR, placental abruption, still birth)
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth
edition, uk , elsevier, 2006 pp 813-829.

24. Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

25. Fetal Effects
• Fetal thyrotoxicosis ( Goitorous)
• Nonimmune hydrops
• Goitrous hypothyroidism
• Nongoitrous hypothyroidism

26. Fetal effect
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

27. Diagnosis
• Thyrotoxicosis usually presents in the late first or early
second trimester.
• Symptoms are as for thyrotoxicosis outside pregnancy,
but these may be unhelpful and commonly reported by
many euthyroid pregnant women (e.g., palmar erythema,
emotional lability, vomiting, goiter. and heat intolerance).
• Discriminatory symptoms may be weight loss, tremor, lid
lag, lid retraction. and a persistent tachycardia greater
than 100 beats/min.
• Diagnosing hyperthyroidism in early pregnancy may be
difficult.
• The diagnosis of hyperthyroidism is confirmed by an
elevated free T4 and/or free T3 with suppressed TSH
levels.
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

28. Therapeutic modalities for hyperthyroidism
can be divided into five categories
• Thionamides (propylthiouracil, carbimazole,
methimazole)- Prevent conversion of T4 to T3 and
reduces the peroxidase function and block
coupling of the idotyrosine.
• β-Blockers-Decrease palpitation as well as
reduces the peripheral conversion of T4 to T3.
• Iodides
• Radioactive iodoine
• Surgery.
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

29. Management
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

30. Management contd….
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

31. Thyroid Storm and Heart Failure
• Both are acute and life-threatening in
pregnancy.
• Thyroid storm is a hypermetabolic state and is
rare in pregnancy.
• In these women, cardiomyopathy is characte
rized by a high-output state, which may lead
to a dilated cardiomyopathy.
• Heart failure develops in 8% of the patient
with uncontrolled hyperthyroidism.
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

32. Thyroid Storm management Protocol
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

33. Hypothyroidism
• Hypothyroidism affects 1% of pregnant
women, and as with hyperthyroidism, many of
the symptoms are encountered in normal
pregnancy.
• 2 and 10 pregnancies per 1000.
• Incidence in nepal is 2.26%

34. Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

35. Causes
• Autoimmune (hashimoto thyroiditis)
• Iatragenic (lithium, amiodarone )
• Transient(de Quervain’s thyroiditis or
postpartum thyroiditis)
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

36. Clinical features
• Fatigue
• Constipation
• Cold intolerance
• Muscle cramps
• Weight gain
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

37. Diagnosis
• Hypothyroidism may be diagnosed in those
with a reduced free T4 concentration in
association with an elevated TSH, which
outside pregnancy, is a sensitive indicator of
the degree of thyroid hormone deficiency.
• Identifying TPO autoantibodies can confirm
the diagnosis, but these are nonspecific, being
present in 20% to 30% of the normal
population.
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

38. Maternal effect
• Myxoedema coma -extremely rare in
pregnancy, but it represents a true
medical emergency with a 20%
mortality rate.
• The clinical picture of myxedema
coma includes hypothermia,
bradycardia, decreased deep tendon
reflexes, and altered consciousness.
• Hyponatremia, hypoglycemia,
hypoxia, and hypercapnia may also be
present.
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

39. Maternal effect
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

40. Fetal effect
• Low IQ Level
• Crentinism
• Neonatal or fetal
hypothyroidism
• Congenital absence of the
thyroid gland
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

41. Management
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,

42. Subclinical hypothyroidism
• If normal thyroid hormone level but elevated
TSH level.
• This thyroid condition is common in women, but
its incidence can be variable depending on age,
race, dietary iodine intake, and serum TSH
thresholds used to establish the diagnosis.
• its prevalence in pregnancy has been estimated
to be between 2 and 5 percent.
• 17% of subclinical hypothyroid women will
develop hypothyroidism in next 20 years.
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

43. Subclinical Hypothyroidism and Pregnancy
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

44. TSH Level Screening in Pregnancy
• The American College of Obstetricians and Gynecologists (2013)
has reaffirmed that although observational data were
consistent with the possibility that subclinical hypothyroidism
was associated with adverse neuropsychological development,
there have been no interventional trials to demonstrate
improvement.
• College thus has consistently recommended against
implementation of screening until further studies are done to
validate or refute these findings.
• The American Thyroid Association, and the American
Association of Clinical Endocrinologists now uniformly
recommend screening only those at increased risk during
pregnancy
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac Graw
Hill , 2014 pp 1147.

45. Isolated Maternal Hypothyroxinemia
• Women with low serum free T4 values but a normal
range TSH level are considered to have isolated maternal
hypothyroxinemia.
• 2.1-percent incidence in the FASTER Trial.
• Offspring of women with isolated hypothyroxinemia
have been reported to have neurodevelopmental
difficulties at age 3 weeks, 10 months, and 2 years.
• CATS study did not find improved neurodevelopmental
outcomes in women with isolated hypothyroxinemia
who were then treated with thyroxine.
• Because of this, routine screening for isolated
hypothyroxinemia is not recommended.
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

46. Postpartum thyroiditis
• Transient autoimmune thyroiditis is consistently
found in approximately 5 to 10 percent of women
during the first year after childbirth.
• Postpartum thyroid dysfunction with an onset
within 12 months includes hyperthyroidism,
hypothyroidism, or both.
• Up to 50 percent of women who are thyroid-
antibody positive in the first trimester will
develop postpartum thyroiditis.
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

47. Nodular Thyroid Disease
• Thyroid nodules can be found in 1 to 2 percent
of reproductiveaged women.
• Management of a palpable thyroid nodule
during pregnancy depends on gestational age
and mass size.
• An important consideration is that, although
rare overall,90% of thyroid cancers present as
thyroid nodules.
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

48. • Carcinomas derived from thyroid epithelium
may be papillary, follicular (differentiated), or
undifferentiated.
• Only those nodules thought to be malignant
need further investigation or treatment, which
is usually by surgery with or without
radioiodine.
Cunninghams . Endocrine disorders: In Williams Obstetrics, 24th Edition, New York, Mac
Graw Hill , 2014 pp 1147.

49. Diagnosis
• Outside pregnancy, radioiodine is used to
distinguish “cold” (more likely to be malignant)
from “hot” (functioning) nodules. Which is
contraindicated in pregnancy.
• Ultrasound, therefore, forms the main
investigative tool.
• Fine-needle aspiration should be reserved for
rapidly enlarging nodules, cystic nodules larger
than 4 cm or solid nodules larger than 2 cm.55
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

50. Management
James, Steer, Weiner.Thyroid disease: in High risk pregnancy management option, fourth edition,
uk , elsevier, 2006 pp 813-829.

51. Take home message
• Thyroid disorder is common in general
population as well as common in pregnant
mother.
• By treating and preventing thyroid condition
we can preserve maternal as well as fetal life.
• Treatment is easy only things required is early
diagnosis and proper management.

52. Thank you

53. • James, Steer, Weiner.Thyroid disease: in High risk
pregnancy management option, fourth edition, uk ,
elsevier, 2006 pp 813-829.
• Cunninghams . Endocrine disorders: In Williams
Obstetrics, 24th Edition, New York, Mac Graw Hill , 2014
pp 1147.
• Richard F .Thyroid anatomy In GRAY’S Anatomy, third
edition , Elseveir, uk , 2015
• Kim E. Thyroid Physiology In Ganong’ Review of Medica
Physiology, 24th edition, New York, Mac Graw Hill ,
2012.