Thyroid disease in pregnancy - Clinicals, Diagnosis, and Management

Obstetrics

Clinicals - 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. 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.
Symptoms of hypothyroidism Fatigue, cold intolerance, poor memory, reduced concentration, constipation, weight gain and hoarseness of voice are the usual symptoms of hypothyroidism. Symptoms of hypothyroidism
Fatigue, cold intolerance, poor memory, reduced concentration, constipation, weight gain and hoarseness of voice are the usual symptoms of hypothyroidism.
Symptoms of hyperthyroidism Patients with hyperthyroidism present with loss of weight, nervousness, tremor, diarrhea, and heat intolerance. Symptoms of hyperthyroidism
Patients with hyperthyroidism present with loss of weight, nervousness, tremor, diarrhea, and heat intolerance.
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. 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.
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. 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.
History of hyperemesis gravidarum Pregnant ladies with morning sickness especially hyperemesis gravidarum can have transient gestational thyrotoxicosis. They commonly present with symptoms of hyperthyroidism. History of hyperemesis gravidarum
Pregnant ladies with morning sickness especially hyperemesis gravidarum can have transient gestational thyrotoxicosis. They commonly present with symptoms of hyperthyroidism.
History of Grave's disease Grave's disease is a common cause for hyperthyroidism. History of Grave's disease
Grave's disease is a common cause for hyperthyroidism.
History of hypothyroidism Common causes of hypothyroidism are chronic autoimmune thyroiditis (Hashimoto’s thyroiditis), iodine deficiency, hitory of radioactive iodine therapy and thyroidectomy. History of hypothyroidism
Common causes of hypothyroidism are chronic autoimmune thyroiditis (Hashimoto’s thyroiditis), iodine deficiency, hitory of radioactive iodine therapy and thyroidectomy.
History of recurrent miscarriages Patients with hyperthyroidism are at risk of spontaneous and recurrent miscarriages. History of recurrent miscarriages
Patients with hyperthyroidism are at risk of spontaneous and recurrent miscarriages.

Clinicals - 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.
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.
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. 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.
Signs of hypothyroidism Patients with hypothyroidism have delayed relaxation of deep tendon reflexes, thin or brittle hair, dry skin, bradycardia and peripheral edema. Signs of hypothyroidism
Patients with hypothyroidism have delayed relaxation of deep tendon reflexes, thin or brittle hair, dry skin, bradycardia and peripheral edema.
Signs of hyperthyroidism Tachycardia, fine tremors, hyper-reflexia, positive ankle clonus and evidence of weight loss are usual signs of hyperthyroidism. Signs of hyperthyroidism
Tachycardia, fine tremors, hyper-reflexia, positive ankle clonus and evidence of weight loss are usual signs of hyperthyroidism.
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 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. 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.

Investigations - 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.
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.
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. 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.
Thyroid hormone receptor antibody (TRAb) TRAb is commonly positive in patients with Grave's disease. Thyroid hormone receptor antibody (TRAb)
TRAb is commonly positive in patients with Grave's disease.
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. 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.
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.
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.

Investigations - Management

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.
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.
ECG Patients with hypothyroidism can have bradycardia and flattened T waves. Hyperthyroidism can induce atrial fibrillation. ECG
Patients with hypothyroidism can have bradycardia and flattened T waves. Hyperthyroidism can induce atrial fibrillation.
Serum TSH levels Universal screening of all pregnant ladies is not indicated. However if the patient has had any thyroid disorders screening is recommended.
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.
Serum TSH levels
Universal screening of all pregnant ladies is not indicated. However if the patient has had any thyroid disorders screening is recommended.
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.

Management - Supportive

Fact Explanation
Health education Patients with thyroid disorders should be educated about the importance of treatment compliance and regular follow up. 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. 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.

Management - Specific

Fact Explanation
Conservative management Patients with transient gestational thyrotoxicosis can be managed conservatively as this usually settles after 16th week of period of amenorrhea. Conservative management
Patients with transient gestational thyrotoxicosis can be managed conservatively as this usually settles after 16th week of period of amenorrhea.
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. 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.
Management of subclinical hypothyroidism Although still doubtful some recommend treatment of subclinical hypothyroidism with levothyroxine. Management of subclinical hypothyroidism
Although still doubtful some recommend treatment of subclinical hypothyroidism with levothyroxine.
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.
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.
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.
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.

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