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Table 1. Risk Factors for Thyroid Dysfunction During Pregnancy
Risk factor Suggested TSH testing frequency
History of (subclinical) hypothyroidism/
hyperthyroidism including postpartum thyroiditis
At presentation of pregnancy
Known thyroid antibody positivity Every 4–6 weeks up to mid-pregnancy
Symptoms of thyroid dysfunction or goiter At presentation of pregnancy
Concurrent medication use associated with thyroid
dysfunction
c
At presentation of pregnancy and
every trimester
Personal history of:
• Autoimmune disease
a
At presentation of pregnancy
• Two or more miscarriages
b
At presentation of pregnancy
• Infertility
b
At presentation of pregnancy
• Down syndrome or Turner syndrome
At presentation of pregnancy
• Treatment with ionizing radiation to the head
and neck region or radioactive iodine
At presentation of pregnancy and
every trimester
• Prior thyroid surgery
At presentation of pregnancy and
every trimester
Family history of autoimmune thyroid disease At presentation of pregnancy
Residing in an area of severe iodine insufficiency
d
while not using iodine-containing supplements or
iodized salt
At presentation of pregnancy
and every 4–6 weeks up to mid-
pregnancy
a
Including but not limited to type 1 diabetes mellitus, pernicious anemia, celiac disease, Addison's
disease, vitiligo, premature ovarian failure, multiple sclerosis, rheumatoid arthritis, and systemic
lupus erythematosus.
b
Screening is only indicated if it was not performed preconception, or if there are other risk factors present.
c
Including but not limited to amiodarone, lithium, rifampin, ethionamide, phenobarbital, phenytoin,
carbamazepine, and recent cancer-related immunotherapy (used within 6 months) or iodinated
contrast (administered within 2 months).
d
As defined by the Iodine Global Network (https://www.ign.org ).
