Download Thyroid Disease in Pregnancy

Thyroid Disease in Pregnancy
Perinatal Conference
April 14, 2006
Thyroid disease in pregnancy
• Affects 1 in 500 women in pregnancy
• Hyperthyroidism - 0.1 to 0.4 percent
• Hypothyroidism – rare in pregnancy
– Elevated TSH – 0.19 to 2.5 percent
Etiology
• Hyperthyroidism
– Graves’s disease
– Autoimmune disease
– Antibodies to thyrotropin receptors on follicular cells in
thyroid
• Hypothyroidism
– Hashimoto’s thyroiditis
– Autoimmune disease
– Antibodies again enzymes that regulate thyroid
hormone synthesis
Thyroid function tests
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Thyrotropin (TSH)
Thyroxine (T4, T3)
T3 uptake
Reverse T3
Thyroglobulin
Thyroid binding globulin
Thyroid stimulating immunoglobulin (TSI) (75% of
Graves’ disease)
– LATS
– TSH receptor antibody
• Thyroid peroxidase (TPO) (70-90% of Hashimoto’s
thyroiditis)
– Antimicrosomal antibody
Clinical symptoms of
hyperthyroidism
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Hyperactivity, irritability, mood swings
Insomnia
Heat and cold intolerance
Palpitations, tachycardia, atrial fibrillation
Tremors
Warm, moist skin
Hair loss
Fatigue, weakness, muscle wasting
Dysnea
Weight loss
Oligomenorrhea
Congestive heart failure
Differential diagnosis of
hyperthyroidism
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Graves’ disease
Multinodular goiter
Solitary autonomous nodule
Subacute thyroiditis
Iodine-induced hyperthyroidism
Exogenous thyroid hormone
Pituitary tumors secreting TSH
Struma ovarii
Tumors secreting hCG (gestational trophoblastic
disease)
Other conditions associated
with Graves’ disease
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Type I diabetes mellitus
Addison’s disease
Vitiligo
Pernicious anemia
Alopecia areata
Myasthenia gravis
Celiac disease
Thyroid disease workup
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CBC
TSH, free T4,
Total T3
Thyroid antibodies
– TSI, TSH receptor
– Anti-thyroid peroxidase, anti-microsomal
• Thyroid ultrasound
TSH receptor antibody
• Thyrotropin receptor antibody (TSH
receptor antibody)
• Also known as thyroid stimulating
immunoglobulin (TSI)
• Also known as long-acting thyroid
stimulator (LATS)
• Present in 77.8% of patients with Grave’s
disease
Thyroid peroxidase antibody
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Also known as TPO, TPOAb
Other names – antimicrosomal antibody
Thyroid peroxidase is an enzyme
Located in thyroid follicular cells
Catalyzes iodination of T4 and T3
Found in 90% of Hashimoto’s thyroiditis
patients
Effects of pregnancy on TFT’s
• Estrogen increases thyroxine-binding
globulin (TBG)
• Total T4 and T3 are increased
• hCG stimulates TSH receptor
• hCG suppresses TSH, 15% of
uncomplicated pregnancies
Risks of hyperthyroidism in
pregnancy
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Gestational hypertension
Preeclampsia
Preterm delivery
Placental abruption
Spontaneous abortion
Treatment of hyperthyroidism
• Propylthiouracil (50-100 mg tid)
– Side effects – rash, bronchospasm, drug fever, hepatitis, oral
ulcers, idiopathic agranulocytopenia
– Breast feeding safe, strongly plasma protein bound
• Methimazole (congenital aplasia cutis, not used in
pregnancy)
• Potassium iodide, Lugol’s solution
• I131
• Surgery – rarely done
• Propranolol
• glucocorticoids
Aplasia cutis
Thyroid disease follow-up
• Labs every 4-6 weeks
– CBC
– LFT’s
– Free T4, total T3, TSH
Subclinical Hyperthyroidism and
pregnancy
• Casey et al, Obstetrics and Gynecology, 2006;
107, 337-41.
– “Subclinical hyperthyroidism and pregnancy
outcomes”
– 25,765 women screened for thyrotropin
– 433 with subclinical hyperthyroidism, low TSH,
normal T4
– Affected women less likely to have pregnancies
complicated by hypertension, OR 0.66 (0.44-0.98)
– No difference in other perinatal morbidity or mortality
Symptoms of hypothyroidism
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Fatigue
Cold intolerance
Constipation
Impaired memory
Slowed mentation
Depression
Ataxia
• Muscle weakness, cramps
• Menstrual disturbance,
infertility
• Bradycardia
• Hoarseness
• Goiter
• Periorbital edema
• Weight gain
Diagnosis of hypothyroidism
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Elevated TSH
Low free T4
Thyroid peroxidase antibody
Antimicrosomal antibody
Risk of hypothyroidism in
pregnancy
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Spontaneous abortion
Fetal growth restriction
Preeclampsia
Postpartum hemorrhage
Subclinical hypothyroidism and
pregnancy
• Haddow et al, NEJM 1999; 341:549-55.
“Maternal thyroid deficiency during pregnancy
and subsequent neuropsychological
development of the child”.
25,216 stored serum, measured thyrotropin.
Contacted women with elevated TSH (n=75)
and matched controls.
IQ tests at age 7-9 years of age of offspring.
Subclinical hypothyroidism and
pregnancy
• Children of women with elevated TSH
scored 4 points lower (P=0.06)
• Children of women with elevated TSH and
untreated scored 7 points lower (P=0.005)
Subclinical hypothyroidism and
pregnancy
• Casey et al, Obstet Gynecol 2005;105:239.
• 25,756 women had routine TSH measured,
17,298 enrolled <20 weeks
• 404, 2.3% were subclinically hypothyroid,
elevated TSH and normal free thyroxine
• 3 times more likely to have placental abruption
• Preterm birth, <34 weeks, 2 fold higher
• No difference in gestational hypertension or
preeclampsia
• No proven therapy, no routine TSH screening