Hyperthyroidism
26
Flowchart 3. Approach to Decreased TSH Levels in
Preconception
• No fertility or pregnancy
contraindication
• No active follow-up,
contact if symptoms
Normal FT4
and (F)T3
If fertility
treatment can
be delayed
Euthyroidism
is achieved
If fertility treatment
is urgent or TSH
normalization unlikely
b
Workup for causes
of hyperthyroidism.
If TSH is persistently
<0.1 mU/L, consider
either intensifying
preconception and
gestational follow-up
or starting low dose
PTU preconception
until a positive
pregnancy test
c
Green boxes indicate a diagnosis, yellow boxes indicate an action, and orange boxes indicate
recommended follow-up.
Subclinical hyperthyroidism
If fertility treatment is
urgent or an underlying
cause cannot be identified
