Hypothyroidism is hypothyroidism, and hypothyroidism may cause early miscarriage. Hypothyroidism causes a decrease in the synthesis and secretion of thyroid hormones, resulting in a low metabolic state in the whole body of the pregnant woman. Untreated pregnant women with reduced synthesis of thyroid hormones will suffer from poor appetite and reduced secretion of estrogen and progesterone, which will lead to malnutrition and endocrine disorders, and will not be able to maintain the normal development of the embryo in the uterus, leading to death of the embryo and causing miscarriage. Pregnant women with hypothyroidism should actively intervene, and timely supplementation of thyroxine after the discovery of hypothyroidism, so that thyroid hormones can be restored to normal levels, which can reduce stillbirths, miscarriages, and fetal malformations. Therefore, pregnant women with combined hypothyroidism should go to the hospital in time and be treated under the guidance of the doctor.