History

Fact Explanation
Asymptomatic Subclinical hypothyroidism can be asymptomatic during the pregnancy. However since it is associated with impaired neurological development of the child early diagnosis and treatment is necessary. Sometimes the hypermetabolic state of the pregnancy may mask the symptoms of hypothyroidism. [1,3]
Symptoms of hypothyroidism Fatigue, cold intolerance, poor memory, reduced concentration, constipation, weight gain and hoarseness of voice are the usual symptoms of hypothyroidism. [4]
Symptoms of hyperthyroidism Patients with hyperthyroidism present with loss of weight, nervousness, tremor, diarrhea, and heat intolerance. [5]
Symptoms of thyroid storm (thyrotoxic crisis) Although rare females with untreated hyperthyroidism can present with symptoms of thyroid storm, which has significant mortality. In addition to symptoms of hyperthyroidism excessive sweating, fever and symptoms of cardiac failure can be present. [1,2]
Symptoms of congestive heart failure Females with hyperthyroidism can develop congestive heart failure. They present with shortness of breath on exertion, orthopnea, paroxysmal nocturnal dyspnea and generalized body swelling. [1]
History of hyperemesis gravidarum Pregnant ladies with morning sickness especially hyperemesis gravidarum can have transient gestational thyrotoxicosis. They commonly present with symptoms of hyperthyroidism. [1]
History of Grave's disease Grave's disease is a common cause for hyperthyroidism. [1]
History of hypothyroidism Common causes of hypothyroidism are chronic autoimmune thyroiditis (Hashimoto’s thyroiditis), iodine deficiency, hitory of radioactive iodine therapy and thyroidectomy. [1]
History of recurrent miscarriages Patients with hyperthyroidism are at risk of spontaneous and recurrent miscarriages. [1]
References
  1. OHASHI MASANAO, FURUKAWA SEISHI, MICHIKATA KAORI, KAI KATSUHIDE, SAMESHIMA HIROSHI, IKENOUE TSUYOMU. Risk-Based Screening for Thyroid Dysfunction during Pregnancy. Journal of Pregnancy [online] 2013 December, 2013:1-5 [viewed 18 August 2014] Available from: doi:10.1155/2013/619718
  2. CARROLL R, MATFIN G. Endocrine and metabolic emergencies: thyroid storm Ther Adv Endocrinol Metab [online] 2010 Jun, 1(3):139-145 [viewed 18 August 2014] Available from: doi:10.1177/2042018810382481
  3. CIGNINI P, CAFà EV, GIORLANDINO C, CAPRIGLIONE S, SPATA A, DUGO N. Thyroid physiology and common diseases in pregnancy: review of literature J Prenat Med [online] 2012, 6(4):64-71 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3530964
  4. GAITONDE DY, ROWLEY KD, SWEENEY LB. Hypothyroidism: an update. Am Fam Physician [online] 2012 Aug 1, 86(3):244-51 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22962987
  5. REID JR, WHEELER SF. Hyperthyroidism: diagnosis and treatment. Am Fam Physician [online] 2005 Aug 15, 72(4):623-30 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16127951

Examination

Fact Explanation
Examination of the thyroid gland Some patients with hyperthyroidism can have a multinodular goiter. Diffusely enlarged thyroid gland can be palpated in Grave's disease. Thyroid bruit indicates increased vascularity of the gland which is commonly detected in Grave's disease. [1]
Ophthalmopathy Ophthalmopathy is common in patients with Grave's disease. Chemosis, opthalmoplegia, proptosis and exopthalmos can be seen. Some patients may have lid lag and lid retraction due to hyperthyroidism. [1]
Signs of hypothyroidism Patients with hypothyroidism have delayed relaxation of deep tendon reflexes, thin or brittle hair, dry skin, bradycardia and peripheral edema. [3]
Signs of hyperthyroidism Tachycardia, fine tremors, hyper-reflexia, positive ankle clonus and evidence of weight loss are usual signs of hyperthyroidism. [4]
Signs suggestive of congestive heart failure Patients with congestive heart failure can have generalized body swelling as indicated by pitting edema. Bibasal pulmonary crepitations can be auscultated if pleural effusions are present.
Signs suggestive of thyroid storm Almost all patients are febrile. Profuse sweating can lead to dehydration. They have high output cardiac failure, as indicated by generalized pitting edema and pulmonary crepitations. Tachyarrhythmia and hypotension are another common associations. [2]
References
  1. OHASHI MASANAO, FURUKAWA SEISHI, MICHIKATA KAORI, KAI KATSUHIDE, SAMESHIMA HIROSHI, IKENOUE TSUYOMU. Risk-Based Screening for Thyroid Dysfunction during Pregnancy. Journal of Pregnancy [online] 2013 December, 2013:1-5 [viewed 18 August 2014] Available from: doi:10.1155/2013/619718
  2. CARROLL R, MATFIN G. Endocrine and metabolic emergencies: thyroid storm Ther Adv Endocrinol Metab [online] 2010 Jun, 1(3):139-145 [viewed 18 August 2014] Available from: doi:10.1177/2042018810382481
  3. GAITONDE DY, ROWLEY KD, SWEENEY LB. Hypothyroidism: an update. Am Fam Physician [online] 2012 Aug 1, 86(3):244-51 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22962987
  4. REID JR, WHEELER SF. Hyperthyroidism: diagnosis and treatment. Am Fam Physician [online] 2005 Aug 15, 72(4):623-30 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16127951

Differential Diagnoses

Fact Explanation
Iron deficiency anemia This is a common cause for reduced exercise tolerance and in advanced cases high output cardiac failure in pregnancy. Reduced hemoglobin (< 10.0 g/dl) and red cell indices showing microcytic hypochromic anemia is diagnostic of iron deficiency anemia. [1,2]
Heart failure Females with heart failure can have exacerbation of symptoms during pregnancy. Females with a history of valvular heart diseases and other congenital heart diseases are at increased risk of heart failure. [3]
Pre-eclampsia Patients with pregnancy induced hypertension can develop preeclampsia. High blood pressure (systolic blood pressure equal or more than 140 mm Hg or diastolic blood pressure equal or more than 90 mm Hg), generalized edema, proteinuria, visual disturbances, severe headache and upper abdominal pain. [4]
References
  1. HAIDER B. A., OLOFIN I., WANG M., SPIEGELMAN D., EZZATI M., FAWZI W. W.. Anaemia, prenatal iron use, and risk of adverse pregnancy outcomes: systematic review and meta-analysis. BMJ [online] December, 346(jun21 3):f3443-f3443 [viewed 18 August 2014] Available from: doi:10.1136/bmj.f3443
  2. UCHE-NWACHI E, ODEKUNLE A, JACINTO S, BURNETT M, CLAPPERTON M, DAVID Y, DURGA S, GREENE K, JARVIS J, NIXON C, SEEREERAM R, POON-KING C, SINGH R. Anaemia in pregnancy: associations with parity, abortions and child spacing in primary healthcare clinic attendees in Trinidad and Tobago Afr Health Sci [online] 2010 Mar, 10(1):66-70 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2895803
  3. IU S. C., SERMER M., COLMAN J. M., ALVAREZ A. N., MERCIER L.-A., MORTON B. C., KELLS C. M., BERGIN M. L., KIESS M. C., MARCOTTE F., TAYLOR D. A., GORDON E. P., SPEARS J. C., TAM J. W., AMANKWAH K. S., SMALLHORN J. F., FARINE D., SORENSEN S.. Prospective Multicenter Study of Pregnancy Outcomes in Women With Heart Disease. Circulation [online] 2001 July, 104(5):515-521 [viewed 18 August 2014] Available from: doi:10.1161/​hc3001.093437
  4. WAGNER LK. Diagnosis and management of preeclampsia. Am Fam Physician [online] 2004 Dec 15, 70(12):2317-24 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/15617295

Investigations - for Diagnosis

Fact Explanation
Serum thyroid-stimulating hormone (TSH) This is the most reliable and relatively inexpensive investigation in the assessment of thyroid function during pregnancy. TSH concentration should be less than 2.5 mIU/L in first trimester (as elevated human chorionic gonadotropin (hCG) causes low TSH levels), less than 3 mIU/L in second trimester and less than 3 mIU/L in third trimester. TSH is elevated in hypothyroidism. Patients with subclinical hypothyroidism have elevated TSH but normal T3 and T4. [1]
Total T3 and T4 levels This also important in the assessment of thyroid status. In hyperthyroidism, low TSH level is associated with increased T3 and T4. Females with hypothyroidism have low levels of free T3 and T4. [1]
Thyroid hormone receptor antibody (TRAb) TRAb is commonly positive in patients with Grave's disease. [1]
Thyroid peroxidase antibody (TPO Ab) This is an autoantibody present in about 10% to 20% of females in child bearing age. Presence of TPO Ab increases the risk of post partum thyroiditis. [1]
Thyroglobulin (TG) autoantibodies As for TPO Ab, TG can also be present in normal population. The risk of post partum thyroiditis is high in those females with TG autoantibodies. Autoantibody screening should not be done in each and every female as this is not cost-effective. [1]
References
  1. OHASHI MASANAO, FURUKAWA SEISHI, MICHIKATA KAORI, KAI KATSUHIDE, SAMESHIMA HIROSHI, IKENOUE TSUYOMU. Risk-Based Screening for Thyroid Dysfunction during Pregnancy. Journal of Pregnancy [online] 2013 December, 2013:1-5 [viewed 18 August 2014] Available from: doi:10.1155/2013/619718

Investigations - Fitness for Management

Fact Explanation
ECG Patients with hypothyroidism can have bradycardia and flattened T waves. Hyperthyroidism can induce atrial fibrillation. [1]
References
  1. GAITONDE DY, ROWLEY KD, SWEENEY LB. Hypothyroidism: an update. Am Fam Physician [online] 2012 Aug 1, 86(3):244-51 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22962987

Investigations - Followup

Fact Explanation
Serum TSH Adequacy of thyroxine replacement should be monitored with routine TSH measurements.TSH should be assessed every four weekly. 6–8 weeks after the delivery TSH levels should be reassessed as dose adjustments are usually necessary after the delivery. [1]
References
  1. CIGNINI P, CAFà EV, GIORLANDINO C, CAPRIGLIONE S, SPATA A, DUGO N. Thyroid physiology and common diseases in pregnancy: review of literature J Prenat Med [online] 2012, 6(4):64-71 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3530964

Investigations - Screening/Staging

Fact Explanation
Serum TSH levels Universal screening of all pregnant ladies is not indicated. However if the patient has had any thyroid disorders screening is recommended. [1] Neonatal screening is recommended for early detection of neonatal hypothyroidism with a heel prick blood sample. This should be carried out between two and four days of birth. [2]
References
  1. OHASHI MASANAO, FURUKAWA SEISHI, MICHIKATA KAORI, KAI KATSUHIDE, SAMESHIMA HIROSHI, IKENOUE TSUYOMU. Risk-Based Screening for Thyroid Dysfunction during Pregnancy. Journal of Pregnancy [online] 2013 December, 2013:1-5 [viewed 18 August 2014] Available from: doi:10.1155/2013/619718
  2. Update of Newborn Screening and Therapy for Congenital Hypothyroidism. PEDIATRICS [online] 2006 June, 117(6):2290-2303 [viewed 18 August 2014] Available from: doi:10.1542/peds.2006-0915

Management - General Measures

Fact Explanation
Health education Patients with thyroid disorders should be educated about the importance of treatment compliance and regular follow up.
Basic life support Patients who present with cardiac failure are preferably treated in an intensive care unit. Assessment of airway, breathing and circulation should be done first. Oxygen should be supplied with a face mask. [1]
References
  1. CARROLL R, MATFIN G. Endocrine and metabolic emergencies: thyroid storm Ther Adv Endocrinol Metab [online] 2010 Jun, 1(3):139-145 [viewed 18 August 2014] Available from: doi:10.1177/2042018810382481

Management - Specific Treatments

Fact Explanation
Conservative management Patients with transient gestational thyrotoxicosis can be managed conservatively as this usually settles after 16th week of period of amenorrhea. [1]
Management of hypothyroidism Maternal hypothyroidism is associated with increased risks for premature birth and low birth weight. So early diagnosis and treatment is mandatory. Levothyroxine (LT4) should be administered (1–2 microg/kg/day) and the dose should be adjusted according to the serum TSH levels four weekly. Generally thyroxine replacement should be increased as the pregnancy progresses. [3,4]
Management of subclinical hypothyroidism Although still doubtful some recommend treatment of subclinical hypothyroidism with levothyroxine. [3]
Management of hyperthyroidism Patients with hyperthyroidism should be given antithyroid drugs to make them euthyroid. Propylthiouracil (PTU) (100–450 mg/day) is the drug of choice. Methimazole (MMI) (10–20 mg/day) can also be prescribed. Propranolol can be given for symptomatic relief as PTU takes about 2 to 4 weeks to act. [4]
Management of thyroid storm Temperature should be gradually brought down. Since most of the patients are dehydrated intravenous fluid should be administered. If present electrolyte imbalance should be corrected. Antipyretics other than salicylates are indicated for the temperature control. If the patient is hemodynamically unstable and having tachyarrhythmia immediate cardioversion by defibrillation should be done. [2]
References
  1. GOLDMAN ALEXANDER M., MESTMAN JORGE H.. Transient Non-Autoimmune Hyperthyroidism of Early Pregnancy. Journal of Thyroid Research [online] 2011 December, 2011:1-11 [viewed 18 August 2014] Available from: doi:10.4061/2011/142413
  2. CARROLL R, MATFIN G. Endocrine and metabolic emergencies: thyroid storm Ther Adv Endocrinol Metab [online] 2010 Jun, 1(3):139-145 [viewed 18 August 2014] Available from: doi:10.1177/2042018810382481
  3. CHANG DONNY L. F., PEARCE ELIZABETH N.. Screening for Maternal Thyroid Dysfunction in Pregnancy: A Review of the Clinical Evidence and Current Guidelines. Journal of Thyroid Research [online] 2013 December, 2013:1-8 [viewed 18 August 2014] Available from: doi:10.1155/2013/851326
  4. CIGNINI P, CAFà EV, GIORLANDINO C, CAPRIGLIONE S, SPATA A, DUGO N. Thyroid physiology and common diseases in pregnancy: review of literature J Prenat Med [online] 2012, 6(4):64-71 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3530964