Hyperthyroidism
42
Table 5. Monitoring Fetal and Neonatal Hyperthyroidism
in Pregnant Women With Active or Past History of
Graves' Disease
Group at risk Recommended monitoring
Pregnant women
with active or past
Graves' disease
(treated with
I-131 or total
thyroidectomy)
• Measure TRAb and/or TSI in the first trimester, and obtain a
monthly fetal ultrasound after 18–20 weeks if the TRAb and/or
TSI level remains >3× the upper limit of normal.
a
• Continually assess for signs and symptoms of fetal
hyperthyroidism by fetal ultrasound.
a
Even in hypothyroid women, high TRAb and/or TSI concentrations can necessitate maternal ATD
treatment (as a vehicle to treat or prevent fetal hyperthyroidism) in combination with levothyroxine
(to maintain maternal euthyroidism).
Table 6A. Signs and Symptoms of Fetal and Neonatal
Hyperthyroidism
Fetus Neonate
• Goiter or thyromegaly (thyroid volume
>90–95th percentile), although this
finding cannot distinguish between fetal
hyperthyroidism and hypothyroidism
• Growth restriction
• Accelerated bone maturation
(distal femoral ossification center visible at
<31 weeks)
• Craniosynostosis
• Heart failure
• Fetal hydrops
• Cardiomegaly
• Tachycardia (persistent heart rate >160–
180 beats per minute) [relatively late sign]
• Intrauterine demise
• Small for gestational age at birth
• Hyperexcitability
• Diarrhea
• Failure to thrive
• Vomiting
• Ophthalmopathy
• Heart failure and cardiac arrhythmias
• Systemic and pulmonary hypertension
• Hepatosplenomegaly
• Jaundice
• Hyperviscosity syndrome
• Thrombocytopenia
• Craniosynostosis
• Small anterior fontanelle
