Thyroid Disorders

The thyroid gland regulates metabolism and has important interactions with the reproductive axis. Hypothyroidism (underactive thyroid) can cause anovulation, irregular cycles, high prolactin, and increased miscarriage risk. Subclinical hypothyroidism (elevated TSH with normal T4) is common and increasingly treated in the fertility context, particularly during pregnancy.

Hyperthyroidism (overactive thyroid) can also disrupt ovulation and increase miscarriage risk. Most fertility specialists recommend TSH testing as part of the initial workup and aim for TSH levels below 2.5 mIU/L in women actively trying to conceive or undergoing ART. Levothyroxine is the standard treatment for hypothyroidism and is safe during pregnancy.