As an important endocrine hormone, thyroid hormone is involved in the normal metabolism of the human body and in the regulation of normal physiological activities, growth and development, reproduction and other organ activities. Studies have shown that pregnancy combined with hypothyroidism or hyperthyroidism may lead to miscarriage, especially subclinical hypothyroidism is closely related to recurrent miscarriage. Indications for thyroid function test: previous abnormal thyroid function and/or family history of abnormal thyroid function; unexplained fetal abortion, recurrent miscarriage; goiter and/or symptoms suspected of hyperthyroidism or hypothyroidism; severe pregnancy vomiting; infertility; polycystic ovary syndrome; abnormal menstruation; diabetes mellitus. Thyroid function test items: mainly include determination of thyroid-related hormones and determination of thyroid autoantibodies. For patients with recurrent miscarriage, thyroid function tests are routinely performed, and depending on the test results, active guidance and treatment are provided to effectively reduce the rate of recurrent miscarriage.