Hypothyroidism
18
Flowchart 1. Approach to Increased TSH Levels in
Preconception
Increased TSH in
preconception
Check FT4
b
Overt
hypothyroidism
Start levothyroxine
1.5–1.7 mcg/kg/day
Start levothyroxine
25–50 mcg/day
Delay pregnancy
Low FT4
Normal FT4
Subclinical
hypothyroidism
Green boxes indicate a diagnosis, yellow boxes indicate an action, and orange boxes indicate
recommended follow-up.
a
Women with a high TSH have a higher risk of TPOAb positivity. TPOAb positivity is associated with
a 7–9% risk of developing subclinical hypothyroidism preconception or during pregnancy. TPOAb
status can guide screening in a future pregnancy and aid in counseling for postpartum thyroiditis risk.
Euthyroid TPOAb positivity is not an indication for levothyroxine (refer to Recommendations Table 7).
