Pregnancy with hypothyroidism may affect the fetus and may lead to miscarriage, and long-term untreated hypothyroidism may lead to neonatal cretinism. When a pregnant woman has hypothyroidism, it may lead to miscarriage or preterm delivery of the fetus, etc. In severe cases, it may cause an increase in the mortality rate of the fetus. Long-term untreated hypothyroidism may also affect the development of the fetus’s nervous system, resulting in mental retardation and slow response, also known as cretinism, commonly known as cretinism. It is recommended that women before or during pregnancy have their thyroid hormone levels measured regularly to detect problems in a timely manner. If a problem is detected, it should be treated with exogenous thyroid hormones on a regular basis under the supervision of a medical professional. Regular reviews should also be done during treatment to ensure that the thyroid function is normal.