is a condition characterized by stunted physical and mental growth due to a congenital deficiency in thyroid hormones usually due to maternal hypothyroidism. Congenital means the condition is present at birth and maternal hypothyroidism means the mother's thryoid gland is not functioning properly. During the first few months of pregnancy, the developing baby depends solely on the mother for its thyroid hormone supply, which is essential for normal growth and brain development. As the pregnancy continues, the baby's thyroid begins to function but the mother continues to supply the thyroid hormone T4. The effects caused by low thyroid hormone levels during pregnancy can be permanent if not corrected soon after birth. Congenital hypothyroidism can also be caused by a defect in the developing baby's thyroid gland. Physical symptoms if untreated may include less than average height, swelling of the skin, loss of water and hair, delayed bone maturation and puberty, thickened skin, enlarged tongue, and protruding abdomen. Delayed ovulation and infertility are also common. There may be mild to severe cognitive impairments as well that include impaired thought and language processes and slower reflexes. If detected early, usually through newborn screening, and treated with thyroxine, then cretinism due to congenital hypothyroidism is almost completely prevented. The term "cretinism" is rarely used anymore due to negative associations with the word. Please also see Congenital hypothyroidism.